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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Sep. 30, 2013	Dec. 16, 2013	Mar. 28, 2013
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Entity Registrant Name	ENANTA PHARMACEUTICALS INC
Entity Central Index Key	0001177648
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		17,961,713
Entity Public Float			$ 221,157,646

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Current assets:
Cash and cash equivalents	$ 8,859	$ 10,511
Short-term marketable securities	92,621	33,251
Accounts receivable	808	1,049
Unbilled receivables	784	1,893
Prepaid expenses and other current assets	1,641	604
Total current assets	104,713	47,308
Property and equipment, net	1,121	611
Long-term marketable securities	10,703	1,656
Restricted cash	436	436
Other assets		2,151
Total assets	116,973	52,162
Current liabilities:
Accounts payable	1,481	1,851
Accrued expenses	3,035	3,866
Deferred revenue	10	17
Total current liabilities	4,526	5,734
Warrant liability	1,620	2,001
Other long-term liabilities	359	498
Total liabilities	6,505	8,233
Commitments and contingencies (Note 15)
Stockholders' equity (deficit):
Common stock; $0.01 par value; 100,000,000 shares authorized; 18,138,597 and 1,343,147 shares issued and 17,929,781 and 1,134,331 shares outstanding at September 30, 2013 and 2012, respectively	181	13
Additional paid-in capital	217,741
Treasury stock, at par value; 208,816 shares at September 30, 2013 and 2012	(2)	(2)
Accumulated other comprehensive income (loss)	(2)	10
Accumulated deficit	(107,450)	(115,374)
Total stockholders' equity (deficit)	110,468	(115,353)
Total liabilities, redeemable and convertible preferred stock and stockholders' equity (deficit)	116,973	52,162
Series C, D, E, F, G-1 and G-2 Redeemable Convertible Preferred Stock [Member]
Current liabilities:
Preferred stock, value		158,955
Series A and B Convertible Preferred Stock [Member]
Current liabilities:
Preferred stock, value		$ 327

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	18,138,597	1,343,147
Common stock, shares outstanding	17,929,781	1,134,331
Treasury stock, shares	208,816	208,816
Series C, D, E, F, G-1 and G-2 Redeemable Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized		45,421,288
Preferred stock, shares issued		43,115,343
Preferred stock, shares outstanding		43,115,343
Preferred stock, aggregate liquidation preference		$ 159,079
Series A and B Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized		566,450
Preferred stock, shares issued		566,450
Preferred stock, shares outstanding		566,450
Preferred stock, aggregate liquidation preference		$ 327

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Statement [Abstract]
Revenue	$ 32,053	$ 41,706	$ 41,882
Operating expenses:
Research and development	16,841	15,115	11,547
General and administrative	6,183	5,302	5,036
Total operating expenses	23,024	20,417	16,583
Income from operations	9,029	21,289	25,299
Other income (expense):
Interest income	248	118	83
Interest expense	(31)		(3,161)
Change in fair value of warrant liability	381	(8)	(686)
Therapeutic tax credit			750
Gain on embedded derivative			670
Other income (expense), net			355
Total other income (expense), net	598	110	(1,989)
Net income	9,627	21,399	23,310
Accretion of redeemable convertible preferred stock to redemption value	(2,526)	(5,367)	(5,454)
Net income attributable to participating securities	(13,670)	(14,663)	(16,291)
Net income (loss) attributable to common stockholders	$ (6,569)	$ 1,369	$ 1,565
Net income (loss) per share attributable to common stockholders:
Basic	$ (0.67)	$ 1.26	$ 1.40
Diluted	$ (0.67)	$ 1.13	$ 1.32
Weighted average common shares outstanding:
Basic	9,788,039	1,088,784	1,119,250
Diluted	9,788,039	2,474,823	1,857,273

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 9,627	$ 21,399	$ 23,310
Other comprehensive income (loss):
Net unrealized gains (losses) on marketable securities, net of tax of $0	(12)	11	(1)
Total other comprehensive income (loss)	(12)	11	(1)
Comprehensive income	$ 9,615	$ 21,410	$ 23,309

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

+ Details

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net unrealized gains (losses) on marketable securities, tax	$ 0	$ 0	$ 0

Consolidated Statements of Changes in Redeemable and Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Series C, D, E, F, G-1 and G-2 Redeemable Convertible Preferred Stock [Member]	Series A and B Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Sep. 30, 2010	$ (150,075)	$ 148,134	$ 327	$ 12		$ (1)		$ (150,086)
Beginning Balance, Shares at Sep. 30, 2010		43,115,343	566,450	1,209,464		(71,926)
Exercise of stock options	$ 34				$ 34
Exercise of stock options, Shares				16,435
Restricted common stock forfeited by former employees					1	$ (1)
Restricted common stock forfeited by former employees, Shares	(208,816)					(136,890)
Compensation expense related to stock options	$ 225				225
Accretion of redeemable convertible preferred stock to redemption value	(5,454)	$ 5,454			(260)			(5,194)
Other comprehensive income (loss)	(1)						$ (1)
Net income	23,310							23,310
Ending Balance at Sep. 30, 2011	(131,961)	$ 153,588	$ 327	$ 12		$ (2)	(1)	(131,970)
Ending Balance, Shares at Sep. 30, 2011		43,115,343	566,450	1,225,899		(208,816)
Exercise of stock options	141			$ 1	140
Exercise of stock options, Shares				117,248
Compensation expense related to stock options	424				424
Accretion of redeemable convertible preferred stock to redemption value	(5,367)	$ 5,367			(564)			(4,803)
Other comprehensive income (loss)	11						11
Net income	21,399							21,399
Ending Balance at Sep. 30, 2012	(115,353)	$ 158,955	$ 327	$ 13		$ (2)	10	(115,374)
Ending Balance, Shares at Sep. 30, 2012		43,115,343	566,450	1,343,147		(208,816)
Exercise of stock options	$ 559			$ 5	554
Exercise of stock options, Shares	538,575			538,575
Compensation expense related to stock options	$ 1,063				1,063
Accretion of redeemable convertible preferred stock to redemption value	(2,526)	$ 2,526			(823)			(1,703)
Conversion of preferred stock to common stock	161,808	$ (161,481)	$ (327)	$ 117	161,691
Conversion of preferred stock into common, Shares		(43,115,343)	(566,450)	11,656,875
Issuance of common stock upon initial public offering	59,892			$ 46	59,846
Issuance of common stock upon initial public offering, Shares				4,600,000
Issuance costs	(4,590)				(4,590)
Other comprehensive income (loss)	(12)						(12)
Net income	9,627							9,627
Ending Balance at Sep. 30, 2013	$ 110,468			$ 181	$ 217,741	$ (2)	$ (2)	$ (107,450)
Ending Balance, Shares at Sep. 30, 2013				18,138,597		(208,816)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities
Net income	$ 9,627	$ 21,399	$ 23,310
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	221	172	499
Non-cash interest expense	31		2,059
Change in fair value of warrant liability	(381)	8	686
Gain on embedded derivative			(670)
Stock-based compensation expense	1,063	424	225
Gain on disposal of property and equipment	(100)	(63)	(7)
Premium on marketable securities	(1,811)
Amortization of premium on marketable securities	1,262	590	317
Change in operating assets and liabilities:
Accounts receivable	241	(788)	(251)
Unbilled receivables	1,109	(1,893)
Prepaid expenses and other current assets	(307)	(235)	(273)
Other assets	22	5	(26)
Accounts payable	115	763	58
Accrued expenses	(285)	1,726	(1,120)
Deferred revenue	(7)	17	(432)
Other long-term liabilities	(147)	498	(356)
Net cash provided by operating activities	10,653	22,623	24,019
Cash flows from investing activities
Purchases of property and equipment	(606)	(252)	(445)
Proceeds from sales of property and equipment		66	9
Purchases of marketable securities	(115,888)	(47,694)	(33,574)
Sales of marketable securities	5,453	15,750	16,764
Maturities of marketable securities	41,825	12,950
Change in restricted cash		1,140	(436)
Net cash used in investing activities	(69,216)	(18,040)	(17,682)
Cash flows from financing activities
Proceeds from issuance of convertible notes			2,000
Repayment of convertible notes			(2,000)
Proceeds from initial public offering, net of underwriting discounts and commissions	59,892
Proceeds from exercise of stock options	559	141	34
Payments of initial public offering costs	(3,540)	(1,050)
Net cash provided by (used in) financing activities	56,911	(909)	34
Net increase (decrease) in cash and cash equivalents	(1,652)	3,674	6,371
Cash and cash equivalents at beginning of period	10,511	6,837	466
Cash and cash equivalents at end of period	8,859	10,511	6,837
Supplemental disclosure of cash flow information:
Cash paid for interest			1,056
Supplemental disclosure of noncash financing activities:
Accretion of redeemable convertible preferred stock to redemption value	2,526	5,367	5,454
Deferred initial public offering costs included in accounts payable and accrued expenses		1,079
Conversion of preferred stock into common stock	$ 161,808

Nature of the Business	12 Months Ended
Nature of the Business	Sep. 30, 2013
Accounting Policies [Abstract]
Nature of the Business	1. Nature of the Business Enanta Pharmaceuticals, Inc. (the “Company”), incorporated in Delaware in 1995, is a research and development-focused biotechnology company that uses its chemistry-driven approach and drug discovery capabilities to create small molecule drugs in the infectious disease field. The Company is developing novel protease, NS5A, cyclophilin and nucleotide polymerase inhibitors targeted against the hepatitis C virus (“HCV”). Additionally, the Company has created a new class of macrolide antibiotics known as Bicyclolides that overcomes bacterial resistance. Antibacterial focus areas include “superbugs,” respiratory tract infections, and intravenous and oral treatments for hospital and community Methicillin-resistant Staphylococcus aureus (“MRSA”). The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, dependence on collaborative arrangements, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance reporting capabilities.

Summary of Significant Accounting Policies

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements include those of the Company and its subsidiary, Enanta Pharmaceuticals Security Corporation, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, management’s judgments of separate units of accounting and best estimate of selling price of those units of accounting within its revenue arrangements; the valuation of outstanding warrants and stock-based awards; the useful lives of property and equipment; and the accounting for income taxes, including uncertain tax positions and the valuation of net deferred tax assets. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates.

Cash Equivalents and Marketable Securities

The Company considers all short-term, highly liquid investments with original maturities of ninety days or less at acquisition date to be cash equivalents. Marketable securities with original maturities of greater than three months and remaining maturities of less than one year from the balance sheet date are classified as short-term marketable securities. Marketable securities with remaining maturities of greater than one year from the balance sheet date are classified as long-term marketable securities.

The Company classifies all of its marketable securities as available-for-sale. All marketable securities are held with one investment manager. The Company continually evaluates the credit ratings of its investment portfolio and underlying securities. The Company invests in accordance with its investment policy and invests at the date of purchase in securities with a rating of A3 or higher and A- or higher according to Moody’s and S&P, respectively. The Company reports available-for-sale investments at fair value as of each balance sheet date and records any unrealized gains and losses as a component of stockholders’ equity (deficit). The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the statement of operations. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate the extent to which the decline is “other than temporary” and reduces the investment to fair value through a charge to the statement of operations. There were no such adjustments necessary during the years ended September 30, 2013, 2012 or 2011.

Restricted Cash

As of September 30, 2013 and 2012, the Company had outstanding a letter of credit collateralized by a money market account of $436 to the benefit of the landlord of the Company’s current office lease. This amount was classified as long-term restricted cash as of September 30, 2013 and 2012.

Concentration of Credit Risk and of Significant Customers and Suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities, accounts receivable and unbilled receivables. The Company has all cash and investment balances at one accredited financial institution, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

The Company has historically generated all of its revenue from its collaborative research and license agreements and a U.S. government contract (see Note 8). As of September 30, 2013 and 2012, accounts receivable and unbilled receivables consisted of amounts due from the Company’s collaborators and under a U.S. government contract (see Note 8).

The Company is completely dependent on third-party manufacturers for product supply for preclinical research activities in its non-partnered programs. In particular, the Company relies and expects to continue to rely exclusively on one manufacturer to supply it with its requirements for the active pharmaceutical ingredients related to these programs. These research programs would be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. A fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last is considered unobservable, is used to measure fair value:

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Level 2—Observable inputs (other than Level 1 quoted prices) such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The Company’s cash equivalents and marketable securities assets and its warrant liabilities are carried at fair value determined according to the fair value hierarchy described above (see Note 3). The carrying values of accounts receivable and unbilled receivables, accounts payable and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. The carrying value of accrued third-party license fees included in other long-term liabilities has been recorded at its present value, which approximates fair value.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation or amortization. Depreciation and amortization expense is recognized using the straight-line method over the following estimated useful lives:


Laboratory and office equipment		3–5 years
Leasehold improvements		Shorter of life of lease or estimated useful life
Purchased software		3–5 years
Computer equipment		3–5 years
Furniture		7 years

Expenditures for repairs and maintenance of assets are charged to expense as incurred. Costs of major additions and betterments are capitalized and depreciated on a straight-line basis over their useful lives. Upon retirement or sale, the cost and related accumulated depreciation or amortization of assets disposed of are removed from the accounts and any resulting gain or loss is included in income (loss) from operations.

Impairment of Long-Lived Assets

The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.

Revenue Recognition

The Company’s revenue is generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables, which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectibility of the resulting receivable is reasonably assured, and the Company has fulfilled its performance obligations under the contract.

For agreements entered into prior to October 1, 2011, the Company evaluated license agreements with multiple deliverables to determine if the deliverable elements could be recognized separately by considering (i) if the delivered elements (typically the license) had standalone value to the customer, (ii) if the fair value of any undelivered elements (typically the research and development services and the steering committee activities) could be determined based on vendor-specific objective evidence (“VSOE”) or vendor objective evidence (“VOE”), and (iii) if the arrangement included a general right of return relative to the delivered item, the delivery or performance of the undelivered item was considered probable and substantially within the control of the Company. VSOE of fair value was based on the consistent price of a deliverable when the Company regularly sold it on a standalone basis. Alternatively, VOE was based upon third-party objective evidence of fair value. If the delivered elements had value on a standalone basis and the fair value of the undelivered elements could be determined based on VSOE or VOE, revenues of such elements were then accounted for separately as delivered with arrangement consideration allocated to the delivered elements based on the residual value method. If either (i) the delivered elements were considered to not have standalone value or (ii) VSOE or VOE of fair value for any of the undelivered elements could not be determined, the arrangement was accounted for as a single unit of accounting and all payments received were recognized as revenue over the estimated period of performance of the entire arrangement.

On October 1, 2011, the Company adopted Accounting Standards Update (“ASU”) No. 2009-13, Multiple-Deliverable Revenue Arrangements (“ASU 2009-13”). This guidance, which applies to multiple-element arrangements entered into or materially modified on or after October 1, 2011, amends the criteria for separating and allocating consideration in a multiple-element arrangement by modifying the fair value requirements for revenue recognition and eliminating the use of the residual value method. The selling prices of deliverables under the arrangement may be derived using third-party evidence (“TPE”) or a best estimate of selling price (“BESP”), if VSOE is not available. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the license agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors including those factors contemplated in negotiating the agreements as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success, and the time needed to commercialize a product candidate pursuant to the license. In validating the Company’s BESP, the Company considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. Deliverables under the arrangement are separate units of accounting if (i) the delivered item has value to the customer on a standalone basis, and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within the control of the Company. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. The appropriate revenue recognition model is applied to each element, and revenue is accordingly recognized as each element is delivered. The Company may exercise significant judgment in determining whether a deliverable is a separate unit of accounting. The Company elected to adopt ASU 2009-13 prospectively as of October 1, 2011.

In determining the separate units of accounting, the Company evaluates whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers whether or not (i) the collaborator can use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license is dependent on the undelivered items, and (iii) the collaborator or other vendors can provide the undelivered items.

Under a collaborative research and license agreement, a steering committee is typically responsible for overseeing the general working relationships, determining the protocols to be followed in the research and development performed, and evaluating the results from the continued development of the product in order to determine the clinical studies to be performed. The Company evaluates whether its participation in joint research and development steering committees is a substantive obligation or whether the services are considered inconsequential or perfunctory. The Company’s participation on a steering committee is considered “participatory” and therefore accounted for as a separate element when the collaborator requires the participation of the Company to ensure all elements of an arrangement are maximized. Steering committee services that are considered participatory are combined with other research services or performance obligations required under an arrangement, if any, in determining the level of effort required in an arrangement and the period over which the Company expects to complete its aggregate performance obligations. Alternatively, the Company’s participation on a steering committee is considered “protective” and therefore not accounted for as a separate element in a case where the Company can exercise or control when to be involved at its own discretion. Factors the Company considers in determining if its participation in a joint steering committee is participating or protective include: (i) which party negotiated or requested the steering committee, (ii) how frequently the steering committee meets, (iii) whether or not there are any penalties or other recourse if the Company does not attend the steering committee meetings, (iv) which party has decision making authority on the steering committee, and (v) whether or not the collaborator has the requisite experience and expertise associated with the research and development of the licensed intellectual property.

For all periods presented, whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model or a straight-line model over the period of performance, which is typically the research and development term. Full-time equivalents (“FTEs”) are typically used as the measure of performance. At each reporting period, the Company reassesses its cumulative measure of performance and makes appropriate adjustments, if necessary. The Company recognizes revenue using the proportional performance model whenever the Company can make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement. Revenue recognized under the proportional performance model at each reporting period is determined by multiplying the total expected payments under the contract (excluding royalties and payments contingent upon achievement of milestones) by the ratio of the level of effort incurred to date to the estimated total level of effort required to complete the performance obligations under the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model as of each reporting period. Alternatively, if the Company cannot make reasonably reliable estimates the level of effort required to complete its performance obligations under an arrangement, then revenue under the arrangement is recognized on a straight-line basis over the period expected to complete the Company’s performance obligations. If and when a contingent milestone payment is earned, the additional consideration to be received is allocated to the separate units of accounting in the arrangement based on their relative selling prices at the inception of the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined on a straight-line basis as of the period end date. If the Company cannot reasonably estimate when its performance obligation period ends, then revenue is deferred until the Company can reasonably estimate when the performance obligation period ends.

Royalty revenue, if any, is recognized based on contractual terms when reported sales are reliably measurable and collectibility is reasonably assured, provided that there are no performance obligations then remaining. To date, none of the Company’s products have been approved, and therefore the Company has not earned any royalty revenue from product sales.

During the years ended September 30, 2013 and 2012, the Company also generated revenue from a government contract under which the Company is reimbursed for certain allowable costs incurred for the funded project. Revenue from the government contract is recognized when the related service is performed. The related costs incurred by the Company under the government contract are included in research and development expense in the statements of operations.

Amounts received prior to satisfying all revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. Amounts not expected to be recognized as revenue within the next twelve months of the balance sheet date are classified as long-term deferred revenue.

In the event that a collaborative research and license agreement is terminated and the Company then has no further performance obligations, the Company recognizes as revenue any portion of the upfront payment that had not previously been recorded as revenue but was classified as deferred revenue at the date of such termination.

Research and Development Costs

Research and development costs are expensed as incurred. Included in research and development costs are wages, stock-based compensation and benefits of employees, third-party license fees and other operational costs related to the Company’s research and development activities, including facility-related expenses and external costs of outside contractors engaged to conduct both preclinical and clinical studies. The Company also includes in research and development expense the costs to complete the Company’s obligations under research collaborations.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are recorded as general and administrative expenses as incurred, as recoverability of such expenditures is uncertain.

Deferred Offering Costs

The Company capitalized certain legal, accounting and other third-party fees that were directly associated with the equity financing that resulted in the Company’s initial public offering of its common stock (“IPO”) in March 2013. Those fees were included in other assets in the accompanying balance sheet until the IPO was consummated. The Company recorded deferred financing costs of $2,129 at September 30, 2012 in other assets in the accompanying balance sheet. After consummation of the IPO, these costs were recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the offering.

Accounting for Stock-Based Compensation

The Company measures all stock options and other stock-based awards granted to employees at the fair value on the date of the grant using the Black-Scholes option-pricing model. The fair value of the awards is recognized as expense, net of estimated forfeitures, over the requisite service period, which is generally the vesting period of the respective award. The straight-line method of expense recognition is applied to all awards with service-only conditions. The Company classifies stock-based compensation expense in the statements of operations in the same manner in which the award recipient’s payroll costs are classified.

Income Taxes

The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

Net Income (Loss) Per Share

The Company follows the two-class method when computing net income (loss) per share during periods before the IPO when the Company had issued shares that met the definition of participating securities. The two-class method is used to determine net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed.

The Company’s redeemable convertible preferred shares and convertible preferred shares contractually entitled the holders of such shares to participate in dividends, but did not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company had participating securities and reported a net loss or a net loss attributable to common stockholders resulting from preferred stock dividends or accretion, net losses were not allocated to participating securities.

Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting net income (loss) attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities, including outstanding stock options and outstanding warrants. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock options and outstanding warrants. For periods in which the Company has reported net losses, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders for the year ended September 30, 2013.

Segment Data

The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is a biotechnology company focused on discovering and developing small molecule drugs in the infectious disease field. Revenue is generated exclusively from transactions occurring in the United States, and all assets are held in the United States.

Comprehensive Income (Loss)

Comprehensive income (loss) includes net income (loss) as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on available-for-sale marketable securities.

Recently Issued and Adopted Accounting Pronouncements

In May 2011, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2011-04, Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs (“ASU 2011-04”). This accounting standard clarifies the application of certain existing fair value measurement guidance and expands the disclosures for fair value measurements that are estimated using significant unobservable (Level 3) inputs. This ASU is effective on a prospective basis for annual and interim reporting periods beginning on or after December 15, 2011. The Company’s adoption of this standard on January 1, 2012 did not have a material effect on its financial position, results of operations or cash flows.

In February 2013, the FASB issued ASU No. 2013-02, Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income (“ASU 2013-02”). This newly issued accounting standard requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the statement where net income is presented or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required under U.S. GAAP to be reclassified to net income in its entirety in the same reporting period. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures required under U.S. GAAP that provide additional detail about those amounts. ASU 2013-02 is effective for fiscal years and interim periods within those years beginning after December 15, 2012 and will become effective for the Company on October 1, 2013. The Company does not believe the adoption of this standard will have an impact on the Company’s financial position, results of operations or cash flows.

In July 2013, The FASB issued ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (“ASU 2013-11”). This newly issued accounting standard requires that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. For example, an entity should not evaluate whether the deferred tax asset expires before the statute of limitations on the tax position or whether the deferred tax asset may be used prior to the unrecognized tax benefit being settled. ASU 2013-11 is effective for fiscal years and interim periods within those years beginning after December 15, 2013 and will become effective for the Company on October 1, 2014. The Company does not believe the adoption of this standard will have an impact on its financial position, results of operations or cash flows.

Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption.

Fair Value of Financial Assets and Liabilities

12 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value of Financial Assets and Liabilities

3. Fair Value of Financial Assets and Liabilities

The following tables present information about the Company’s financial assets and liabilities that were subject to fair value measurement on a recurring basis as of September 30, 2013 and 2012 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value:


	Fair Value Measurements as of September 30, 2013 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	7,517	$	—	$	—	$	7,517
U.S. Treasury notes		1,005		—		—		1,005
Commercial paper		—		10,596		—		10,596
Corporate bonds		—		84,755		—		84,755
U.S. Agency bonds		—		3,518		—		3,518
Certificate of deposit		—		3,450		—		3,450

	$	8,522	$	102,319	$	—	$	110,841

Liabilities:
Warrant liability	$	—	$	—	$	1,620	$	1,620

	$	—	$	—	$	1,620	$	1,620


	Fair Value Measurements as of September 30, 2012 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	6,471	$	—	$	—	$	6,471
U.S. Treasury notes		1,015		—		—		1,015
Commercial paper		—		8,143		—		8,143
Corporate bonds		—		25,749		—		25,749

	$	7,486	$	33,892	$	—	$	41,378

Liabilities:
Warrant liability	$	—	$	—	$	2,001	$	2,001

	$	—	$	—	$	2,001	$	2,001

During the years ended September 30, 2013, 2012 and 2011, there were no transfers between Level 1, Level 2 and Level 3.

Cash equivalents at September 30, 2013 and 2012 consist of money market funds.

As of September 30, 2013, the warrant liability consists solely of the warrants for the purchase of Series 1 nonconvertible preferred stock. As of September 30, 2013, the Company utilized a probability weighted valuation model which takes into consideration various outcomes that may require the Company to transfer assets upon exercise. The fair value of these outstanding warrants to purchase our Series 1 nonconvertible preferred stock as recorded in the balance sheet was $1,620 and $1,981 at September 30, 2013 and 2012, respectively. The Series E warrants expired during the year ended September 30, 2013.

The recurring Level 3 fair value measurements of the Company’s warrant liability using probability-weighted discounted cash flow include the following significant unobservable inputs:


	Unobservable Input	Range (Weighted Average)
Warrant Liability	Probabilities of payout	25% - 90%

	Periods in which payout is expected to occur	2014 - 2018

	Discount rate	4.25%

The fair value of warrants for the purchase of Series E redeemable convertible preferred stock (see Note 12) was $20, as of September 30, 2012. These warrants expired unexercised in fiscal 2013.

The following table provides a rollforward of the aggregate fair values of the Company’s warrants for the purchase of Series E preferred stock and Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs:


Balance, September 30, 2010	$	26
Warrants issued		1,280
Increase in fair value		705
Decrease in fair value		(18	)

Balance, September 30, 2011		1,993
Warrants expired		(8	)
Increase in fair value		19
Decrease in fair value		(3	)

Balance, September 30, 2012		2,001
Warrants expired		(20	)
Decrease in fair value		(361	)

Balance, September 30, 2013	$	1,620

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Marketable Securities

12 Months Ended

Sep. 30, 2013

Investments Debt And Equity Securities [Abstract]

Marketable Securities

4. Marketable Securities

As of September 30, 2013 and 2012, the fair value of available-for-sale marketable securities by type of security was as follows:


	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	10,596	$	—	$	—		$	10,596
Corporate bonds		84,757		23		(25	)		84,755
U.S. Agency bonds		3,519		—		(1	)		3,518
Certificate of deposit		3,450		—		—			3,450
U.S. Treasury notes		1,004		1		—			1,005

	$	103,326	$	24	$	(26	)	$	103,324


	September 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	8,143	$	—	$	—		$	8,143
Corporate bonds		25,741		9		(1	)		25,749
U.S. Treasury notes		1,013		2		—			1,015

	$	34,897	$	11	$	(1	)	$	34,907

At September 30, 2013, marketable securities consisted of investments that mature within one year, with the exception of certain corporate bonds, which have maturities within two years and an aggregate fair value of $10,703. At September 30, 2012, marketable securities consisted of investments that mature within one year, with the exception of one U.S. Treasury note and one corporate bond, which have maturities within two years and an aggregate fair value of $1,656.

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Property and Equipment

12 Months Ended

Sep. 30, 2013

Property Plant And Equipment [Abstract]

Property and Equipment

5. Property and Equipment

Property and equipment consisted of the following as of September 30, 2013 and 2012:


	September 30,
	2013			2012
Laboratory and office equipment	$	4,395		$	4,142
Leasehold improvements		272			268
Purchased software		438			402
Computer equipment		90			76
Furniture		263			259

		5,458			5,147
Less: Accumulated depreciation and amortization		(4,337	)		(4,536	)

	$	1,121		$	611

Depreciation and amortization expense was $221, $172 and $499 for the years ended September 30, 2013, 2012 and 2011, respectively. During the years ended September 30, 2013, 2012 and 2011, assets with a cost of $420, $273 and $3,810, respectively, were sold or disposed of, resulting in a gain of $100, $63 and $7, respectively.

Accrued Expenses and Other Long-Term Liabilities

12 Months Ended

Sep. 30, 2013

Payables And Accruals [Abstract]

Accrued Expenses and Other Long-Term Liabilities

6. Accrued Expenses and Other Long-Term Liabilities

Accrued expenses (current) and other long-term liabilities consisted of the following as of September 30, 2013 and 2012:


	September 30,
	2013		2012
Accrued expenses:
Accrued payroll and related expenses	$	1,041	$	1,305
Accrued vendor manufacturing		989		1,330
Accrued professional fees		378		718
Accrued third-party license fee		240		222
Accrued other		387		291

	$	3,035	$	3,866

Other long-term liabilities:
Accrued rent expense	$	127	$	75
Present value of accrued third-party license fee		184		423
Asset retirement obligation		48		—

	$	359	$	498

Convertible Notes

12 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Convertible Notes

7. Convertible Notes

2011 Bridge Financing

In October 2010, the Company entered into a convertible note and warrant purchase agreement with existing investors to sell, in one or more closings, term notes in the aggregate principal amount of up to $6,500. The term notes had an interest rate of 5% per annum, with principal and interest payable at the stated maturity date of October 4, 2011 or earlier if put to the Company by the noteholders or if called by the Company. The noteholders could put the term notes to the Company for early repayment upon receipt by the Company of the next milestone payment under the Company’s collaborative development and license agreement with Abbott Laboratories (subsequently AbbVie, as explained in Note 8 below) or upon a merger, sale or liquidity event as specified by the note agreement. The Company could call the term notes for early repayment at any time. If called by the Company prior to maturity, repaid at maturity, or put by the noteholders upon receipt by the Company of the milestone payment, the term notes required payment of a prepayment premium equal to 51.8% of the principal amount of the notes in addition to the principal and interest payable. If put by the noteholders due to a liquidity event, the term notes were not subject to the premium of 51.8% but were to be repaid at the following multiples:

•

two times the principal amount if the liquidity event occurred on or before March 31, 2011, and

•

three times the principal amount if the liquidity event occurred after March 31, 2011.

During the first closing of the term notes in October and November 2010, the Company borrowed a total of $2,000. The remaining balance of $4,500 under the agreement was not drawn down.

The call and put options within the notes agreement constituted an embedded derivative, which was required to be separately recognized and measured at fair value, resulting in the Company recognizing a debt discount and derivative liability of $670 at the date of issuance of the notes.

In addition, each purchaser of a note received warrants to purchase shares of Series 1 nonconvertible preferred stock (the “Nonconvertible Preferred”) at the rate of one warrant for each dollar of the original purchase amount of the note. The warrants have an exercise price of $0.01 per share. At issuance, the number of shares issuable upon exercise of the warrants was not yet fixed. The number of shares for which the warrants could be exercisable was (i) one share for each dollar of the original principal amount of the Note, plus (ii) if the milestone payment was not received on or before March 31, 2011, an additional share for each dollar of the original principal amount of the notes. Additionally, if a liquidation event occurred, thereby requiring repayment of the term notes, these warrants would automatically expire and would therefore have no value. At the date of issuance, the warrants were valued using the Black-Scholes option-pricing model for each of the two scenarios described above. A decision tree was used to estimate the probability of how many shares the warrants would ultimately be exercised into or if the warrants would have no value under the third scenario. This resulted in a total fair value of $1,280 at date of issuance. Upon repayment of the notes in December 2010, the number of shares issuable upon exercise of the warrants became fixed at 1,999,989 Nonconvertible Preferred shares. Additionally, the possibility that the notes would not be redeemed and that the warrants would therefore have no value was eliminated. Accordingly, at the time of the note repayment in December 2010, the Company revalued the warrants, which resulted in a total fair value of $1,983. The change in the fair value of the warrants was recorded within other income (expense) in the statement of operations. Additionally, as these warrants are financial instruments that may require a future transfer of assets, they are classified as liabilities on the balance sheet. Upon issuance of the notes and warrants, the fair value of the warrants was recorded as a warrant liability and a corresponding debt discount was recognized. The warrants are remeasured at each balance sheet date (see Note 3), and the change in fair value is recorded within other income (expense).

Following the receipt by the Company of a $40,000 milestone payment from Abbott Laboratories in December 2010 (see Note 8), the Company repaid the $2,000 in principal plus the accrued interest of $20 and the applicable premium of $1,036 (51.8% of the principal amount). Upon repayment of the notes, the unamortized debt discount derived from both the embedded derivatives and the warrants was accreted as a charge to interest expense and the derivative liability (recorded at fair value) was removed, resulting in a gain recorded in the statement of operations. The warrants, however, remained outstanding as of September 30, 2013. The note agreement was canceled upon the December 2010 repayment and no further warrants were issued under the agreement.

In connection with this financing, the Company incurred issuance costs of $41 during the year ended September 30, 2011. These costs were initially recorded as deferred financing costs in other assets on the balance sheet. In December 2010, upon repayment of the notes, the total deferred financing costs of $150 were charged to interest expense.

Collaboration Agreements	12 Months Ended
Collaboration Agreements	Sep. 30, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	8. Collaboration Agreements AbbVie Collaboration On November 27, 2006, the Company entered into a Collaborative Development and License Agreement with Abbott Laboratories (“Abbott”) to identify, develop and commercialize HCV NS3 and NS3/4A protease inhibitor compounds, including ABT-450. On January 1, 2013, Abbott announced that it had completed the spin-off of its research-based pharmaceuticals business into a new, independent biopharmaceutical company named AbbVie Inc. (“AbbVie”). AbbVie was formed to hold Abbott’s research-based pharmaceuticals business and, as a result of the spin-off, became an independent public company. In connection with the spin-off, Abbott assigned to AbbVie the above Collaborative Development and License Agreement (“AbbVie Agreement”). Under the terms of the AbbVie Agreement, as amended, through September 30, 2009, AbbVie paid $48,300 to the Company for upfront license payments and FTE reimbursements to fund research activities. The Company is also eligible to receive milestone payments for the successful development by AbbVie of one or more HCV compounds as well as tiered royalties per product ranging from the low double digits up to twenty percent, or up to the high teens on a blended basis, on net sales by AbbVie allocable to the collaboration’s protease inhibitors. Also on November 27, 2006, the Company entered into a Series G preferred stock purchase agreement with AbbVie. In connection with that agreement, the Company sold to AbbVie 4,620,764 shares of Series G-1 redeemable convertible preferred stock at a price of $2.70518 per share, resulting in gross proceeds of $12,500. Due to the simultaneous issuance of Series G-2 redeemable convertible preferred stock to a third party unrelated to AbbVie which had similar terms to Series G-1 but a lower price per share, the Company determined that the Series G-1 redeemable convertible preferred stock sold to AbbVie was issued at a premium of $1,617. The Company aggregated this premium with the upfront payments received and recorded it as deferred revenue to be recognized over the period of performance under the AbbVie Agreement. In January 2009, the Company and AbbVie amended the AbbVie Agreement to include an option for AbbVie to opt into an evaluation period that would commence upon the termination or expiration of the research program term and continue for a period of six months. During the evaluation period, AbbVie would have the right to analyze certain compounds for the purpose of identifying any suitable for further development. In December 2009, the Company and AbbVie further amended the AbbVie Agreement to extend funding of the research activities for another year through December 2010. In December 2010, AbbVie opted into the evaluation period and additional research activities for the six-month evaluation period ended June 15, 2011. In connection with these amendments, AbbVie paid the Company an additional $4,150 for the research services performed from December 15, 2009 through June 15, 2011. On December 17, 2010, the Company received a milestone payment of $40,000 for the successful completion of AbbVie’s Phase 2a clinical study. During the year ended September 30, 2013, the Company received an additional $15,000 milestone payment under the AbbVie Agreement as a result of AbbVie’s initiation of dosing in a Phase 3 clinical trial of a regimen that included ABT-450. Through September 30, 2013, the Company had received upfront license payments, research funding, and milestone payments totaling $107,450 under the AbbVie Agreement. As of September 30, 2013, the Company is eligible to receive additional future milestone payments totaling up to $40,000 upon AbbVie’s achievement of regulatory filing milestones for the first protease inhibitor product resulting from its collaboration and additional milestone payments totaling up to $155,000 upon AbbVie’s achievement of commercial regulatory approval milestones in selected world markets. The Company is also eligible to receive additional milestone payments totaling up to $80,000 upon AbbVie’s achievement of similar commercial regulatory approval milestones for each additional product containing a protease inhibitor. The Company determined that the deliverables under the AbbVie Agreement included (i) the non-exclusive, royalty-free, worldwide research license and the exclusive, royalty-bearing development and commercialization license, (ii) the research services, and (iii) a commitment to participate on a steering committee, all of which were to be delivered over a three-year period. The Company concluded that the license did not have standalone value as it was dependent, in part, upon the Company’s continuing involvement in the HCV protease inhibitor research and its involvement in the joint steering committee. Additionally, the undelivered items, including the Company’s participation in the joint steering committee, which was considered participatory due to its decision making responsibilities, and the research services, did not have VSOE or VOE of fair value. Therefore, the license, the research services, and the joint steering committee participation were treated as a single unit of accounting. Accordingly, all amounts received were deferred, and revenue was recognized using the proportional performance model over the period during which the Company performed research services in connection with the AbbVie Agreement, as amended. Under this model, the revenue recognized was limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model, as of each reporting period. At each reporting period, the Company updated its estimates of effort remaining to complete its obligations under the AbbVie Agreement, the expected term over which the obligations would be performed, and the total expected revenue based on all known information. Based on the obligations and responsibilities of the joint steering committee, the Company determined that the obligation to participate in the joint steering committee was participatory only through the research and evaluation period, which ended June 15, 2011. Subsequent to the research and evaluation period, all decisions related to the development, commercialization and marketing are to be made by AbbVie. The Company has the right to continue to attend the joint steering committee meetings to monitor the development and marketing plans; however, the Company has no decision making rights. As such, the joint steering committee commitment became protective in nature as of June 16, 2011. During fiscal 2010 and 2011, revenue related to the AbbVie Agreement was recognized in the amounts of $6,518 and $41,882, respectively. In fiscal 2011, the Company completed all remaining obligations under the agreement. As a result no revenue was recognized related to this agreement during the year ended September 30, 2012. Since all obligations under the AbbVie Agreement were concluded by the end of fiscal 2011, any future milestone payments received will be recognized as revenue when each milestone is achieved by AbbVie. During fiscal 2013 the Company earned and recognized as revenue a $15,000 milestone payment based on AbbVie’s initiation of dosing in a Phase 3 clinical trial that included ABT-450. The Company has the option, but not the obligation, to co-develop and share in the profit of any product in the United States that is developed as a result of the AbbVie Agreement. This option for the first compound (ABT-450) expired in fiscal 2011. The Company has no further obligations in regard to the AbbVie Agreement and will evaluate future options as they arise. Royalties owed to the Company under the agreement can be reduced by AbbVie in certain circumstances, including (i) if AbbVie exercises its right to license or otherwise acquire rights to intellectual property controlled by a third party where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, (ii) where a product developed under the collaboration agreement is sold in a country and not covered by a valid patent claim in such country, and (iii) where sales of a generic product are equal to at least a specified percentage of AbbVie’s market share of a product in a country. AbbVie’s obligation to pay royalties on a product developed under the agreement expires on a country-by-country basis upon the later of (i) the last date upon which the manufacture, use or sale of a product would infringe one of the licensed patents, and (ii) ten years after the first commercial sale of the product in the applicable country. Subject to certain exceptions, a party’s rights and obligations under the agreement continues until (i) such time as AbbVie is no longer developing a product candidate or (ii) if, as of the time AbbVie is no longer developing any product candidates, AbbVie is commercializing any other protease inhibitor product, such time as all royalty terms for all covered products and all co-development terms for all co-developed products have ended. Accordingly, the final expiration date of the agreement is currently indeterminable. Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice. If the Company terminates the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted the Company (i) a non-exclusive, perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate, and (ii) an exclusive (even as to AbbVie), perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in any joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds. Upon the Company’s request, AbbVie will also transfer to the Company all right, title and interest in any related product trademarks, regulatory filings and clinical trials. If AbbVie terminates the agreement for the Company’s uncured breach, the milestone and royalty payments payable by AbbVie may be reduced, the licenses granted to AbbVie will remain in place, the Company will be deemed to have granted AbbVie an exclusive license under the Company’s interest in joint intellectual property, AbbVie will continue to have the right to commercialize any covered products, and all rights and licenses granted to the Company by AbbVie will terminate. Novartis Collaboration On February 16, 2012, the Company entered into a license and collaboration agreement with Novartis (the “Novartis Agreement”) for the development, manufacture and commercialization of its lead development candidate, EDP-239, from its NS5A HCV inhibitor program. Under the terms of the Novartis Agreement, Novartis agreed to pay a nonrefundable upfront fee to the Company and reimbursement of manufacturing and quality assurance expenses related to EDP-239 totaling $34,442. In November 2012, a clinical milestone payment of $11,000 was earned and recognized as revenue upon Novartis’ initiation of dosing in the first Phase 1 clinical trial involving EDP-239. Under the Novartis Agreement, the Company is eligible to receive additional milestone payments totaling up to $395,000 upon Novartis’ initiation of clinical trials, achievement of regulatory approvals, and/or net sales of products containing the Company’s NS5A inhibitors, including a milestone payment of $15,000 that will be due upon Novartis’ initiation of the first Phase 2 clinical trial using a combination containing an NS5A inhibitor from the collaboration. The Company is also eligible to receive tiered royalties ranging on a blended basis from the low double digits up to the high teens on net product sales by Novartis allocable to the collaboration’s NS5A inhibitors. In addition, Novartis agreed to fund research activities for one year commencing February 2012, up to a total of $1,800. In March 2013, the Novartis Agreement was amended to extend research funding for an additional six months at the same reimbursement rate. The Company determined that the deliverables under the Novartis Agreement include (i) the exclusive, royalty-bearing, sublicensable license to EDP-239 and (ii) the research services. The Company concluded that the EDP-239 license had standalone value to Novartis and was separable from the research services as the license is sublicensable, there are no restrictions as to Novartis’ use of the license and Novartis has the requisite scientific expertise in the HCV NS5A field. The Company also concluded that its participation on the joint steering committee, as provided by the agreement, is protective in nature as the Company has no decision making authority, there are no penalties or recourse if the Company chooses not to participate, and the purpose of the steering committee is to keep the Company apprised as to the status of the development and commercialization efforts. Therefore, no arrangement consideration was allocated to the joint steering committee participation. The Company was not able to establish VSOE or TPE for either the license or the research services and instead allocated the arrangement consideration between the license and research services based on their relative selling prices using BESP. The Company developed its estimate of BESP of the license using a discounted cash flow analysis, taking into consideration assumptions including the development and commercialization timeline, discount rate, probability of success, and probable treatment combination and associated peak sales figures that generate royalty amounts. The funding rate for the research services is consistent with the rate received in the Company’s prior collaboration arrangement with AbbVie and is consistent with its fully burdened cost of service. Therefore, the Company’s determination of BESP for the research services is consistent with the reimbursement rate stated in the contract. These assumptions involve judgment and inherent uncertainty; however, significant changes in key assumptions used to determine the BESP would not have a significant effect on the total amount of revenue recognized. The Company received an upfront cash payment of $34,442 in March 2012 related to the Novartis Agreement. The Company recognized the entire upfront cash receipt as revenue because the allocated selling price of the license deliverable exceeded the upfront noncontingent cash payments received. During the year ended September 30, 2012, the Company recognized total revenue of $35,567 related to the delivery of the license and the performance of the research services. During the year ended September 30, 2013, the Company recognized total revenue of $12,675 under the Novartis Agreement, of which $10,894 was attributable to license fees and $1,781 was attributable to the performance of research services. Subject to certain exceptions, on a country-by-country and product-by-product basis, a party’s rights and obligations under the agreement continue until the later of (i) the expiration of the last to expire patent rights of a covered product in the applicable country or (ii) ten years from the first commercial sale of a covered product in the applicable country. As a result, the final expiration date of the Novartis license is indeterminable at this time. Upon expiration of the agreement with respect to a particular product and country, the licenses granted to Novartis in the agreement with respect to such product and country will remain in effect and convert to a nonexclusive, perpetual, unrestricted, fully paid, royalty-free, worldwide license. The Company may terminate the agreement (i) in the event of a material breach by Novartis, subject to prior notice and the opportunity to cure, (ii) in the event Novartis fails to use commercially reasonable efforts to develop and commercialize covered products in its territory, or (iii) in the event Novartis is subject to an insolvency event. Novartis may terminate the agreement (i) in the event of a material breach by the Company, subject to prior notice and the opportunity to cure, (ii) in the event the Company is subject to an insolvency event, or (iii) for any reason upon 120 days prior written notice. In the case of a termination for cause by the Company or a termination without cause by Novartis, any licenses and other rights granted by either party to the other will terminate and revert back to the granting party and the Company will regain control of the prosecution of the patents relating to the Company’s intellectual property. If such termination occurs prior to the second anniversary of the end of the research term, the Company obtains a worldwide, exclusive, fully paid, perpetual license, with the right to sublicense, under all collaboration intellectual property owned in whole or in part by Novartis, to research, develop and commercialize compounds and products contemplated by the collaboration. If such termination occurs after the second anniversary of the end of the research term, then Novartis agrees to negotiate with the Company to grant it a worldwide, exclusive, field-limited, royalty-bearing license, with right to sublicense, under all collaboration intellectual property owned in whole or in part by Novartis. NIAID Contract On September 30, 2011, the Company entered into a contract with the National Institute of Allergy and Infectious Diseases (“NIAID”), a division of the National Institutes of Health (“NIH”), which contract could provide up to $42,700 in development funding to the Company over a five-year period. The contract will fund the preclinical and clinical development of a new class of bridged bicyclic antibiotics known as Bicyclolides to be used as medical countermeasures against multiple biodefense Category A and B bacteria. The contract has an initial term of 30 months ending on March 30, 2014. NIAID has the option to extend the contract up to six times. If each extension option is exercised, the contract would be extended until September 30, 2016. The initial award under the initial term was $14,300, with the possibility of up to a total of $42,700 if each option period is exercised by NIAID. In August 2013 NIAID exercised the first two options under this agreement which obligate it to provide an additional $9,200 in funding to the Company for preclinical and early clinical development of EDP-788, bringing total funding paid or committed to date by NIAID to approximately $23,500 through February 2015. The Company recognizes revenue under this agreement as development services are performed in accordance with the funding agreement. During the year ended September 30, 2012, $6,139 of revenue was recognized under this agreement, of which $1,049 was invoiced but unpaid and included in accounts receivable and $1,668 was unpaid and included in unbilled receivables on the Company’s balance sheet as of September 30, 2012. During the year ended September 30, 2013, the Company recognized revenue of $4,378, under this agreement, of which $258 was invoiced but unpaid and included in accounts receivable and $784 was unpaid and included in unbilled receivables at September 30, 2013. NIAID may terminate performance of work under this contract if it determines that a termination is in the government’s interest or if the Company defaults in performing the contract. After termination, the Company would submit a final termination settlement proposal in order to settle all outstanding liabilities, including those arising from the termination of subcontracts, the cost of which would be reimbursable in whole or in part, under this contract, contingent on approval by NIAID. If the Company and NIAID fail to agree in whole or in part on the amount of costs to be paid because of the termination of work, NIAID shall determine, on the basis of information available, the amount to be repaid.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Sep. 30, 2013
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity On March 1, 2013, the Company effected an increase in the number of authorized shares of its common stock from 70,000,000 to 100,000,000 shares. On March 1, 2013, the Company effected a 1-for-4.31 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratio for each series of redeemable convertible preferred stock and convertible preferred stock. Accordingly, all share and per share amounts for all periods presented in these financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the reverse stock split and adjustment of the preferred share conversion ratios. On March 26, 2013 the Company completed an initial public offering of its common stock, which resulted in the sale of 4,600,000 shares. The Company received net proceeds from the IPO of $59,892 based upon the price of $14.00 per share and after deducting underwriting discounts and commissions paid by the Company. Upon the closing of the initial public offering, all outstanding shares of the Company’s redeemable convertible preferred stock and convertible preferred stock were converted into 11,656,875 shares of common stock. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive such dividends as may be declared by the board of directors, if any. During the year ended September 30, 2011, the Company reacquired 208,816 shares of restricted common stock that were forfeited by former employees. The Company recorded these shares as treasury stock at their par value.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Paragraph 1
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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-Paragraph d
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
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-Name Regulation S-X (SX)
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Reference 16: http://www.xbrl.org/2003/role/presentationRef
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Reference 17: http://www.xbrl.org/2003/role/presentationRef
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Reference 18: http://www.xbrl.org/2003/role/presentationRef
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Reference 19: http://www.xbrl.org/2003/role/presentationRef
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-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Preferred Stock

12 Months Ended

Sep. 30, 2013

Equity [Abstract]

Preferred Stock

10. Preferred Stock

Redeemable convertible preferred stock consisted of the following as of September 30, 2012:


	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Liquidation Preference		Carrying Value		Common Stock Issuable Upon Conversion
Series C redeemable convertible preferred stock		2,543,603		2,543,603	$	8,551	$	8,551		590,159
Series D redeemable convertible preferred stock		5,968,334		5,968,334		37,922		37,922		1,853,953
Series E redeemable convertible preferred stock		16,132,546		14,368,037		66,136		66,136		4,386,373
Series F redeemable convertible preferred stock		6,894,966		6,894,966		15,000		15,000		1,599,760
Series G-1 redeemable convertible preferred stock		4,729,543		4,620,764		12,500		12,376		1,072,103
Series G-2 redeemable convertible preferred stock		9,152,296		8,719,639		18,970		18,970		2,023,110

		45,421,288		43,115,343	$	159,079	$	158,955		11,525,458

Upon the closing of the initial public offering, all outstanding shares of the Company’s redeemable convertible preferred stock were converted into 11,525,458 shares of common stock.

Prior to the conversion, the rights and preferences of the Company’s outstanding redeemable convertible preferred stock were as follows:

Voting Rights

Holders of all redeemable convertible preferred stock had the right to vote the number of shares equal to the number of shares of common stock into which such redeemable convertible preferred stock could be converted into on the date for determination of stockholders entitled to vote at a meeting or on the date of any written consent.

Dividends

Holders of the Series C redeemable convertible preferred stock, Series D redeemable convertible preferred stock and Series E redeemable convertible preferred stock were entitled to receive, out of funds legally available, cumulative dividends at an annual rate of 7%, 9% and 9%, respectively, when and if declared by the board of directors. Holders of the Series F redeemable convertible preferred stock and Series G-1 and G-2 redeemable convertible preferred stock were entitled to receive, out of funds legally available, noncumulative dividends at an annual rate of 7%, if declared by the board of directors. No dividends were declared or paid through conversion date.

The Company recorded cumulative dividends and accretion to redemption value through charges to stockholders’ deficit of $2,526 and $5,367 in fiscal 2013 and 2012, respectively, in connection with these dividend and redemption rights.

Liquidation Preference

In the event of any liquidation, dissolution or winding up of the Company, inclusive of a sale of the Company, a sale of the capital stock representing a majority of the voting power or a merger or consolidation of the Company into or with another corporation in which the existing Company held less than 80% of the voting power of the surviving or resulting corporation, the Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stockholders were entitled to receive, in preference to all other stockholders, except for holders of Series 1 Nonconvertible Preferred stock, and to the extent available, an amount equal to the original offering price per share ($2.51, $2.1755, $2.70518 and $2.1755, respectively, adjusted for any stock dividends, stock splits or reclassifications) plus all dividends declared but unpaid.

Holders of Series E redeemable convertible preferred stock were to receive with their preference all cumulative dividends, whether or not declared. In the event that proceeds were not sufficient to permit payment in full to these holders, the proceeds were to be ratably distributed among Series E, F, G-1 and G-2 holders in proportion to the full preferential amount each such holder was otherwise entitled to receive.

After the Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stockholders were paid, and to the extent available, the Series D redeemable convertible preferred stockholders were entitled to receive, in preference to all other stockholders, an amount equal to the original offering price per share ($3.00, adjusted for any stock dividends, stock splits or reclassifications) plus all cumulative Series D dividends, whether or not declared.

After the Series D redeemable convertible preferred stockholders were paid, and to the extent available, the Series C redeemable convertible preferred stockholders were entitled to receive an amount equal to the original offering price per share ($1.72, adjusted for any stock dividends, stock splits or reclassifications) plus all cumulative Series C dividends, whether or not declared.

After payments were made in full to the Series 1 Nonconvertible Preferred stockholders, if any, to the holders of the Series G-1, Series G-2, Series F, Series E, Series D and Series C redeemable convertible preferred stock and to the holders of the Series B and Series A convertible preferred stock, to the extent available, holders of the common stock and holders of the Series C, Series D and Series E redeemable convertible preferred stock were to receive the remaining amounts available for distribution ratably in proportion to the number of common shares held by them or issuable to them upon conversion of their preferred stock into common stock. The distributions were subject to an overall distribution limit of two times the original purchase price per share of the Series C, Series D and Series E redeemable convertible preferred stock.

Conversion

Each share of redeemable convertible preferred stock was convertible into common stock at the option of the stockholder at any time after the date of issuance. Each share of the preferred stock automatically converted into shares of common stock at the applicable Series C, Series D, Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stock conversion ratio upon the closing of the Company’s initial public offering on March 26, 2013. The conversion ratio of the Series C, Series D, Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stock as defined was $1.72, $3.00, $2.51, $2.1755, $2.70518 and $2.1755, respectively. The conversion prices of Series C, Series D, Series E, Series F, Series G-1 and G-2 redeemable convertible preferred stock were $7.41320, $9.65772, $8.22176, $9.37641, $11.65933 and $9.37641, respectively. As a result, all outstanding shares of Series D redeemable convertible preferred stock converted into common stock on a 0.31063-for-1 basis, all outstanding shares of Series E redeemable convertible preferred stock converted into common stock on a 0.30529-for-1 basis, and all outstanding shares of Series C, Series F, Series G-1 and G-2 redeemable convertible preferred stock converted into common stock on a 0.23202-for-1 basis.

Redemption Rights

At the written election of the majority of the holders of the Series C, Series D, Series E, Series F or Series G-1 and G-2 redeemable convertible preferred stock, the shares of Series C, Series D, Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stock outstanding prior to conversion were redeemable in installments commencing December 31, 2013. The carrying values of the Series C, Series D, Series E, Series F and Series G-1 and G-2 redeemable convertible preferred stock were being accreted to their redemption values through their respective redemption dates.

Reissuance

Shares of any Series C, Series D, Series E, Series F or Series G-1 or G-2 redeemable convertible preferred stock that were redeemed or converted were retired or canceled and are not reissuable by the Company.

Convertible preferred stock, which was not redeemable, consisted of the following as of September 30, 2012:


	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Liquidation Preference		Carrying Value		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		379,450		379,450	$	140	$	140		88,033
Series B convertible preferred stock		187,000		187,000		187		187		43,384

		566,450		566,450	$	327	$	327		131,417

Upon the closing of the initial public offering, all outstanding shares of the Company’s convertible preferred stock were converted into 131,417 shares of common stock.

Prior to the conversion, the holders of the Convertible Preferred Stock had the following rights and preferences:

Voting Rights

Holders of all convertible preferred stock had the right to vote the number of shares equal to the number of shares of common stock into which such preferred shares could be converted into on the date for determination of stockholders entitled to vote at a meeting or on the date of any written consent.

Dividends

If dividends were declared and paid on the shares of Series A or Series B convertible preferred stock, the Company was required to declare at the same time a dividend payable with respect to the Series C, Series D, Series E, Series F, Series G-1 and G-2 redeemable convertible preferred stock equivalent to the dividend amount they would receive if all convertible preferred shares were converted into common stock. The Company could not pay dividends to the holders or the Series A and Series B convertible preferred stock until all cumulative dividends accrued but unpaid on Series C, Series D, Series E, Series F, Series G-1 and G-2 redeemable convertible preferred stock had been paid in full. Holders of the Series A and B convertible preferred stock were not entitled to receive cumulative dividends.

Liquidation Preference

In the event of any liquidation, dissolution or winding up of the Company, inclusive of a “deemed liquidation” (defined as a sale of the Company, a sale of the capital stock representing a majority of the voting power, or a merger or consolidation of the Company into or with another corporation of the Company in which the existing Company holds less than 80% of the voting power of the surviving or resulting corporation), after the holders of the Series 1 nonconvertible preferred stock, if any, and redeemable preferred stock had been paid, and to the extent available, holders of Series A and Series B convertible preferred stock were entitled to receive an amount equal to the original offering price per share ($0.37 for Series A convertible preferred stock and $1.00 for Series B convertible preferred stock, adjusted for any stock dividends, stock splits or reclassifications) plus all dividends declared but unpaid.

Conversion

Each share of Convertible Preferred Stock was convertible into common stock at the option of the holder at any time after the date of issuance. Each share of the convertible preferred stock automatically converted into shares of common stock at the applicable conversion ratio upon the closing of the Company’s initial public offering on March 26, 2013. All outstanding shares of Series A and Series B convertible preferred stock converted into common stock on a 0.23202-for-1 basis.

Redemption Rights

There were no redemption rights afforded the Series A and Series B convertible preferred stock. The holders of Series A and Series B convertible preferred stock had liquidation rights in the event of a deemed liquidation that, in certain situations, were not solely within the control of the Company. Therefore, the Series A and Series B convertible preferred stock was classified outside of stockholders’ deficit.

Reissuance

Shares of any Series A or Series B convertible preferred stock that were converted into common stock were retired or canceled and are not reissuable by the Company.

Series 1 Nonconvertible Preferred Stock

The Company’s Certificate of Incorporation authorizes the issuance of up to 1,999,989 shares of Series 1 Nonconvertible Preferred Stock (the “Series 1 Nonconvertible Preferred”) at a par value of $0.01 per share. As of September 30, 2013 and 2012, there were no shares of Series 1 Nonconvertible Preferred issued or outstanding. Holders of Series 1 Nonconvertible Preferred stock are not entitled to receive dividends. In the event of any liquidation, deemed liquidation, dissolution or winding up of the Company, the Series 1 Nonconvertible Preferred stockholders are entitled to receive in preference to all other stockholders, an amount equal to $1.00 per share, adjusted for any stock dividends, stock splits or reclassifications. Series 1 Nonconvertible Preferred holders will not be entitled to vote unless required by the Company pursuant to the laws of the State of Delaware. The Company may redeem the Series 1 Nonconvertible Preferred stock with the approval of the holders of a majority of the outstanding shares of Series 1 Nonconvertible Preferred at a redemption price of $1.00 per share. The Company must redeem the stock within 60 days of such election. Shares that are redeemed will be retired or canceled and not reissued by the Company.

If all outstanding warrants to purchase the Series 1 Nonconvertible Preferred stock are exercised, the resulting outstanding shares of Series 1 Nonconvertible Preferred stock will carry an aggregate $2,000 liquidation preference that is superior to the common stock and any other classes of preferred stock then outstanding.

Common Stock Warrants	12 Months Ended
Common Stock Warrants	Sep. 30, 2013
Text Block [Abstract]
Common Stock Warrants	11. Common Stock Warrants As of September 30, 2010, warrants to purchase 345,952 shares of common stock were outstanding. The value of these warrants was classified as equity as these warrants were exercisable into common stock only and, as such, would not require a transfer of assets. In October 2010, these warrants expired unexercised. As a result, as of September 30, 2013 and 2012, no common stock warrants were outstanding.

Preferred Stock Warrants

12 Months Ended

Sep. 30, 2013

Text Block [Abstract]

Preferred Stock Warrants

12. Preferred Stock Warrants

Warrants to Purchase Series E Preferred Stock

Warrants for the purchase of Series E redeemable convertible preferred stock (“Series E preferred stock”) were issued by the Company in fiscal 2002 and fiscal 2004 during various financings. As these warrants were financial instruments that would require a transfer of assets because of the redemption feature at the option of the holders of the Series E preferred stock, these warrants were classified as liabilities on the Company’s balance sheet at September 30, 2012.

As of September 30, 2011, warrants for the purchase of 341,556 shares of Series E preferred stock were outstanding. During the year ended September 30, 2012, warrants for the purchase of 329,056 shares expired. As of September 30, 2012, warrants for the purchase of 12,500 shares of Series E preferred stock remained outstanding. These warrants expired during the year ended September 30, 2013.

The Company is required to remeasure the fair value of these preferred stock warrants at each reporting date, with any adjustments recorded as other income (expense). The warrants outstanding at each reporting date were remeasured using the Black-Scholes option-pricing model, and the resulting change in fair value was recorded in other income (expense) in the statement of operations. As a result, the Company recorded income of $18 for the year ended September 30, 2011, and expense of $19 for the year ended September 30, 2012, related to the change in fair value of the warrants. The Company also recorded income of $8 for the year ended September 30, 2012 related to the expiration of 329,056 warrants. As of September 30, 2012, the total fair value of the outstanding Series E preferred stock warrants was $20. During the year ended September 30, 2013, the Company recorded income of $20 related to the expiration of the Series E preferred stock warrants.

Warrants to Purchase Series 1 Preferred Stock

In October and November 2010, a total of 1,999,989 warrants to purchase Series 1 nonconvertible preferred stock were issued. These warrants expire on October 4, 2017. As these warrants are free-standing financial instruments that may require the Company to transfer assets upon exercise, these warrants are classified as liabilities. These warrants had a fair value upon issuance of $1,280. The Company is required to remeasure the fair value of these preferred stock warrants at each reporting date, with any adjustments recorded within the change in fair value of warrant liability included in other income (expense) in the statement of operations. The warrants were remeasured at each reporting period, resulting in net income of $361 and $3 for the years ended September 30, 2013 and 2012, respectively. As of September 30, 2013 and 2012, the total fair value of the Series 1 nonconvertible preferred stock warrants was $1,620 and $1,981, respectively.

The following table summarizes the Company’s warrant activity since October 1, 2010:


	Common Stock Exercisable			Weighted Average Exercise Price		Series E Preferred Stock Exercisable			Weighted Average Exercise Price		Series 1 Preferred Stock Exercisable		Weighted Average Exercise Price
Outstanding, as of September 30, 2010		345,952		$	8.40		341,556		$	2.51		—
Granted		—					—					1,999,989
Expired		(345,952	)				—					—
Exercised		—					—					—

Outstanding, as of September 30, 2011		—					341,556		$	2.51		1,999,989	$	0.01
Granted		—					—					—
Expired		—					(329,056	)				—
Exercised		—					—					—

Outstanding, as of September 30, 2012		—					12,500		$	2.51		1,999,989	$	0.01
Granted		—					—					—
Expired		—					(12,500	)				—
Exercised		—					—					—

Outstanding, as of September 30, 2013		—					—					1,999,989	$	0.01

Stock-Based Awards

12 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Awards

13. Stock-Based Awards

In 2012 the Company’s Board adopted the 2012 Equity Incentive Plan (the “2012 Plan”), which was subsequently approved by the stockholders and became effective immediately prior to the closing of the Company’s initial public offering on March 26, 2013. The 2012 Plan permits the Company to sell or issue common stock or restricted common stock, and to grant incentive stock options or nonqualified stock options for the purchase of common stock, restricted stock units, stock appreciation rights or other cash incentive awards, to employees, members of the board of directors and consultants of the Company. The total number of shares of common stock that could be issued under the plan initially was 321,613 shares, plus additional shares from the 1995 Equity Incentive Plan that had not been issued or reserved for future issuance upon exercise of options. The number of shares of common stock that may be issued under the 2012 Plan is also subject to increase on the first day of each fiscal year by the lowest of (i) 3% of the Company’s outstanding shares of common stock as of that date, (ii) 2,088,167 shares of common stock, or (iii) an amount determined by the board of directors.

The 2012 Plan replaces and is the successor to the 1995 Equity Incentive Plan (the “1995 Plan”). The 1995 Plan provided for the Company to sell or issue common stock or restricted common stock, or to grant incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the board of directors and consultants of the Company. Sales, issuances or grants of shares entitle the holder to purchase common stock from the Company, for a specified exercise price, during a period specified by the applicable equity award agreement. The 1995 Plan is administered by the board of directors and exercise prices, vesting and other restrictions are all determined at their discretion.

Options granted under the 1995 Plan to non-executive employees generally vest 25% per year and expire after ten years; options granted to executive employees generally vest over one to four years; and options granted to the board of directors vest over two to three years. The total number of shares of common stock that could be issued under the 1995 Plan was 2,540,759 shares as of September 30, 2012. On January 17, 2013, the Company’s stockholders approved an amendment to the 1995 Plan to increase the number of shares of common stock reserved for issuance under the 1995 Plan to 2,772,777 shares. Upon the closing of the Company’s initial public offering, all remaining shares reserved for issuance under the 1995 Plan were transferred to the 2012 Plan, of which 346,038 shares remained available for future grant as of September 30, 2013, and no further awards will be made under the 1995 Plan.

On January 3, 2013, the Company’s stockholders approved an Employee Stock Purchase Plan (“ESPP”). A total of 185,614 shares of common stock are reserved for issuance under this plan, which became effective immediately prior the closing of the Company’s initial public offering. As of September 30, 2013, the Company had not commenced any offering under the ESPP and no shares have been issued.

The Company applies the fair value recognition provisions for all stock-based awards granted or modified. In the case of service-based awards, the compensation cost is recorded over the requisite service period of the award on the straight-line method based on the grant-date fair value. The requisite service period for service-based awards is generally four years, with restrictions lapsing evenly over the period.

In March 2013, the Company granted to certain executives 167,052 options that vest upon the achievement of certain performance-based targets. The fair value of these options at the grant date was $1,487. In April 2013, the terms of the options were modified resulting in an immaterial change in the fair value of the options. Through September 30, 2013, the Company recorded no compensation expense related to these options as none of the performance-based targets was deemed to be probable of being achieved.

Stock Option Valuation

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Prior to March 2013 the Company had been a private company and lacked company-specific historical and implied volatility information. Therefore, the Company estimated its expected stock volatility based on the historical volatility of its publicly traded peer companies inclusive of the Company, commencing March 2013 and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The relevant data used to determine the value of the stock option grants is as follows, presented on a weighted average basis:


	Year Ended September 30,
	2013			2012			2011
Risk-free interest rate		1.05	%		0.93	%		2.73	%
Expected term (in years)		6.09			6.00			6.25
Expected volatility		73	%		78	%		87	%
Expected dividend yield		0	%		0	%		0	%

The Company recognizes compensation expense for only the portion of awards that are expected to vest. In developing a forfeiture rate estimate, the Company has considered its historical experience to estimate pre-vesting forfeitures for service-based awards. The impact of a forfeiture rate adjustment will be recognized in full in the period of adjustment, and if the actual forfeiture rate is materially different from the Company’s estimate, the Company may be required to record adjustments to stock-based compensation expense in future periods.

As required by the 1995 Plan and 2012 plan, the exercise price for awards granted is not to be less than the fair value of common shares as estimated by the Company as of the date of grant. For the periods prior to the March 2013 IPO, the Company valued its common stock by taking into consideration its most recently available valuation of common shares performed by management and the board of directors as well as additional factors which may have changed since the date of the most recent contemporaneous valuation through the date of grant. For the periods after the IPO, the Company based fair value of its common stock on the quoted market price.

The following table summarizes stock option activity for the year ended September 30, 2013:


	Shares Issuable Under Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding as of September 30, 2012		1,771,471		$	2.08		4.1	$	19,911
Granted		364,318			14.21
Exercised		(538,575	)		1.04
Forfeited		(11,319	)		12.54
Expired		(2,864	)		2.59

Outstanding as of September 30, 2013		1,583,031		$	5.15		5.0	$	28,133

Options vested and expected to vest as of September 30, 2013		1,408,344		$	4.06		4.5	$	26,568

Options exercisable as of September 30, 2013		1,161,570		$	2.33		3.5	$	23,919

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock for those shares that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised was $7,574, $606 and $10 during the years ended September 30, 2013, 2012 and 2011, respectively.

The Company received cash proceeds from the exercise of stock options of $559, $141 and $34 during the years ended September 30, 2013, 2012 and 2011, respectively. The weighted average grant date fair value of options granted during the years ended September 30, 2013, 2012 and 2011 was $9.16, $7.79 and $1.95, respectively.

The Company recorded stock-based compensation expense for the years ended September 30, 2013, 2012 and 2011 in the following expense categories:


	Year Ended September 30,
	2013		2012		2011
Research and development	$	393	$	126	$	66
General and administrative		670		298		159

	$	1,063	$	424	$	225

As of September 30, 2013, the Company had an aggregate of $1,416 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.8 years.

Net Income (Loss) Per Share

12 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Net Income (Loss) Per Share

14. Net Income (Loss) Per Share

Basic and diluted net income (loss) per share attributable to common stockholders was calculated as follows for the years ended September 30, 2013, 2012 and 2011:


	Year Ended September 30,
	2013			2012			2011
Basic net income (loss) per share attributable to common stockholders:
Numerator:
Net income	$	9,627		$	21,399		$	23,310
Accretion of redeemable convertible preferred stock to redemption value		(2,526	)		(5,367	)		(5,454	)
Net income attributable to participating securities		(13,670	)		(14,663	)		(16,291	)

Net income (loss) attributable to common stockholders	$	(6,569	)	$	1,369		$	1,565

Denominator:
Weighted average common shares outstanding—basic		9,788,039			1,088,784			1,119,250

Net income (loss) per share attributable to common stockholders—basic	$	(0.67	)	$	1.26		$	1.40


	Year Ended September 30,
	2013			2012			2011
Diluted net income (loss) per share attributable to common stockholders:
Numerator:
Net income	$	9,627		$	21,399		$	23,310
Accretion of redeemable convertible preferred stock to redemption value		(2,526	)		(5,367	)		(5,454	)
Net income attributable to participating securities		(13,670	)		(13,225	)		(15,401	)

Net income (loss) attributable to common stockholders—diluted	$	(6,569	)	$	2,807		$	2,455

Denominator:
Weighted average common shares outstanding—basic		9,788,039			1,088,784			1,119,250
Dilutive effect of common stock equivalents		—			1,386,039			738,023

Weighted average common shares outstanding—diluted		9,788,039			2,474,823			1,857,273

Net income (loss) per share attributable to common stockholders—diluted	$	(0.67	)	$	1.13		$	1.32

Stock options for the purchase of 1,713,313 weighted average shares were excluded from the computation of diluted net loss per share attributable to common stockholders for the year ended September 30, 2013 because those options had an anti-dilutive impact due to the net loss attributable to common stockholders.

Stock options for the purchase of 33,359 and 594,453 weighted average shares were excluded from the computation of diluted net income per share attributable to common stockholders for the years ended September 30, 2012 and 2011, respectively because those options had an anti-dilutive impact due to the assumed proceeds per share using the treasury stock method being greater than the average fair value of the Company’s common shares for those periods.

Warrants outstanding as of September 30, 2011 for the purchase of 341,556 shares of Series E preferred stock were excluded from the calculations of diluted net income per share attributable to common stockholders for the year ended September 30, 2011 because those warrants had an anti-dilutive impact due to the assumed proceeds per share using the treasury stock method being greater than the average fair value of the Company’s common shares for that year.

Commitments and Contingencies

12 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

15. Commitments and Contingencies

Leases

During the year ended September 30, 2011, the Company signed a seven-year lease for new office space that began on October 1, 2011. The lease provides for payment escalations during the term of the lease. Payment escalations as specified in the lease agreements are accrued such that rent expense is recognized on a straight-line basis over the terms of occupancy. The Company incurred rent expense of $948, $948 and $1,995, respectively, for the years ended September 30, 2013, 2012 and 2011.

Future minimum lease payments for operating leases as of September 30, 2013 are as follows:


Year ending September 30,
2014		921
2015		946
2016		972
2017		999
2018		1,027

Total	$	4,865

The Company previously leased office space in Watertown, Massachusetts under a ten-year lease that expired at the end of September 2011. In connection with the prior office lease, the Company issued a $1,140 letter of credit through November 2011 to the benefit of the landlord, collateralized by a certificate of deposit. On December 2, 2011, the landlord released the letter of credit to the Company. In connection with the new lease, the Company issued a $436 letter of credit, collateralized by a money market account. As of September 30, 2013 and 2012, the Company classified amounts of $436 in each year, as restricted cash relating to this lease.

Intellectual Property Licenses

During the year ended September 30, 2012, in response to correspondence the Company received from a third party related to assets the Company used or may have used in prior periods, the Company entered into a non-exclusive intellectual property license agreement with the third party. Under the agreement, the Company is required to pay the third party licensor an upfront license fee of $350 and additional license fees of $250 on the first anniversary, $250 on the second anniversary and $200 on the third anniversary of the agreement. In addition, the Company is required to pay (1) annual maintenance fees of $105 for each year that the agreement remains in effect, commencing on the first anniversary of the agreement, in order to maintain the right to use the license, and (2) a one-time fee of $50 in each circumstance in which the Company provides the licensed intellectual property to one of its collaborators with the prior consent of the licensor. As a result, during fiscal 2012, the Company recorded in research and development expense a total of $895 of license expense, which represented the fair value of the payments that the Company believed related to its use of the assets in fiscal 2012 and prior periods. As of September 30, 2012, the Company had recorded liabilities totaling $995 related to the agreement. Of that amount, $350 was included in accounts payable, $222 was included in accrued expenses and $423 was included in other long-term liabilities on the balance sheet at September 30, 2012. During the year ended September 30, 2013, the Company paid $350 due under the agreement. As of September 30, 2013, the Company had recorded liabilities totaling $674 in connection with the agreement, of which $250 was included in accounts payable, $240 was included in accrued expenses and $184 was included in other long-term liabilities on the balance sheet.

Future non-cancelable minimum payments under the agreement are as follows:


Year ending September 30,
2014		250
2015		200

Total	$	450

As of September 30, 2012, the Company was aware of a potential license it may need to acquire with respect to patents it used, or may have used, in its HCV research during prior years or periods. As of September 30, 2012, the Company believed that license costs were probable, but a range of the loss could not be reasonably estimated; therefore, no accrual for this matter was recorded as of September 30, 2012. During the year ended September 30, 2013, the Company obtained an amendment to an existing license agreement to extend rights to patents previously licensed for one of its programs for use in its other HCV research. Under the amended agreement, the Company is obligated to pay milestones totaling up to $5,000, plus low single digit royalties, for each HCV product it develops and obtains regulatory approval outside of its collaboration with AbbVie or any other collaboration it may enter into in the future with a partner that has already licensed these patents. In the same period, the Company paid a milestone payment of $500 under this amended agreement.

Litigation and Contingencies Related to Use of Intellectual Property

From time to time, the Company may become subject to legal proceedings, claims and litigation arising in the ordinary course of business. The Company currently is not a party to any threatened or pending litigation. However, third parties might allege that the Company or its collaborators are infringing their patent rights or that the Company is otherwise violating their intellectual property rights. Such third parties may resort to litigation against the Company or its collaborators, which the Company has agreed to indemnify. With respect to some of these patents, the Company expects that it will be required to obtain licenses and could be required to pay license fees or royalties, or both. These licenses may not be available on acceptable terms, or at all. A costly license, or inability to obtain a necessary license, could have a material adverse effect on the Company’s financial condition, results of operations or cash flows. The Company accrues contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to customers, vendors, lessors, business partners, and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements, from services to be provided by the Company, or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. In addition, the Company maintains officers and directors insurance coverage. The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its financial statements as of September 30, 2013 or 2012.

Income Taxes

12 Months Ended

Sep. 30, 2013

Income Tax Disclosure [Abstract]

Income Taxes

16. Income Taxes

During the years ended September 30, 2013, 2012 and 2011, no provision for income taxes was recorded due primarily to the Company’s use of net operating loss carryforwards to fully offset the income before income taxes of $9,627, $21,399 and $21,310, respectively, generated in those periods. As the deferred tax assets for those utilized net operating loss carryforwards had previously been recorded with a full valuation allowance, the use of the net operating loss carryforwards in each of those periods resulted in an income tax benefit being recognized, which substantially offset the tax provision recorded as a result of the income before income taxes generated.

In all periods presented, all income before income taxes was sourced from the United States.

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended September 30,
	2013			2012			2011
Federal statutory income tax rate		34.0	%		34.0	%		34.0	%
State taxes, net of federal benefit		5.5			5.4			5.8
Federal research and development tax credit		(2.5	)		(0.2	)		(2.0	)
Change in deferred tax asset valuation allowance		(51.0	)		(40.1	)		(40.5	)
Other		14.0			0.9			2.7

Effective income tax rate		0.0	%		0.0	%		0.0	%

Net deferred tax assets as of September 30, 2013 and 2012 consisted of the following:


	September 30,
	2013			2012
Net operating loss carryforwards	$	8,495		$	10,961
Tax credit carryforwards		6,111			5,731
Capitalized research and development expenses		6,953			9,750
Other temporary differences		1,333			1,357

Gross deferred tax assets		22,892			27,799
Valuation allowance		(22,892	)		(27,799	)

Net deferred tax assets	$	—		$	—

As of September 30, 2013, the Company had net operating loss carryforwards for federal and state income tax purposes of $24,107 and $5,653, respectively, which begin to expire in fiscal 2018 and 2015, respectively. The Company also has available research and development tax credit and other credit carryforwards for federal and state income tax purposes of $4,375 and $2,631, respectively, which begin to expire in fiscal 2021 and 2016, respectively. Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 due to ownership changes that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income.

During the years ended September 30, 2013, 2012 and 2011, gross deferred tax assets related to net operating loss carryforwards decreased due to their utilization as a result of income before income taxes generated during those periods.

The Company has concluded, based on the weight of available evidence, that its net deferred tax assets are not more likely than not to be realized in the future. Management has considered the Company’s history of cumulative net losses incurred since inception, its lack of commercialization of any products or generation of any revenue from product sales since inception and its inability to reasonably estimate the timing or amounts, if any, of future milestone payments it will receive from its collaborators, and concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets. Accordingly, a full valuation allowance has been established against the deferred tax assets as of September 30, 2013 and 2012. Management reevaluates the positive and negative evidence at each reporting period.

Changes in the valuation allowance for deferred tax assets during the years ended September 30, 2013, 2012 and 2011 were as follows:


	Year Ended September 30,
	2013			2012			2011
Valuation allowance as of beginning of year	$	27,799		$	36,369		$	45,812
Decreases recorded as benefit to income tax provision		(4,907	)		(8,570	)		(9,443	)
Increases recorded to income tax provision		—			—			—

Valuation allowance as of end of year	$	22,892		$	27,799		$	36,369

The Company has not recorded any amounts for unrecognized tax benefits as of September 30, 2013 or 2012.

The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending income tax examinations. The Company’s tax years are still open under statute from 2009 to the present. Earlier years may be examined to the extent that tax credit or net operating loss carryforwards are used in future periods. The Company’s policy is to record interest and penalties related to income taxes as part of its income tax provision.

401(k) Plan	12 Months Ended
401(k) Plan	Sep. 30, 2013
Postemployment Benefits [Abstract]
401(k) Plan	17. 401(k) Plan In December 1999, the Company established a 401(k) plan. This plan covers substantially all employees who meet minimum age and service requirements. Under the terms of the plan, the Company contributes on an annual basis up to 2% of an employee’s base salary up to a maximum of $4 per employee. During the years ended September 30, 2013, 2012 and 2011, the Company recognized $90, $84 and $95, respectively, of expense related to its contributions to this plan.

Related Party Transactions	12 Months Ended
Related Party Transactions	Sep. 30, 2013
Related Party Transactions [Abstract]
Related Party Transactions	18. Related Party Transactions The Company has entered into consulting agreements for research and development and business management activities with certain members of the Company’s board of directors. Consulting fees expensed and paid for each of the years ended September 30, 2013, 2012 and 2011 were $10, $75 and $75. As further described in Note 7, the Company had entered into a note and warrant purchase agreement with stockholders in fiscal 2011.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Qualifying Therapeutic Discovery Project Program	12 Months Ended
Qualifying Therapeutic Discovery Project Program	Sep. 30, 2013
Text Block [Abstract]
Qualifying Therapeutic Discovery Project Program	19. Qualifying Therapeutic Discovery Project Program In November 2010, the Company received notification from the Internal Revenue Service that it had been awarded grants for four research projects under the Qualifying Therapeutic Discovery Project Credit program, covering 50% of qualifying expenses incurred, up to a maximum of $244 for each of the four projects. During the year ended September 30, 2011, the Company recorded the proceeds of $750 in other income (expense) in the statement of operations, upon approval of the qualifying expenses. A payment of $489 was received in fiscal 2011 for work on two of the projects already carried out during fiscal 2010. For the two projects carried out during fiscal 2011, a total amount receivable of $261 was recorded as of September 30, 2011, and was received in full in October 2011.

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Sep. 30, 2013

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

20. Selected Quarterly Financial Data (unaudited)

Quarterly financial information for fiscal 2013 and 2012 is presented in the following table, in thousands, except per share data:


	2013 Quarter Ended
	December 31, 2012			March 31, 2013			June 30, 2013			September 30, 2013
Revenue	$	27,859		$	1,196		$	1,649		$	1,349
Operating expenses		5,950			5,197			5,827			6,050
Other income (expense), net		48			252			40			258
Net income (loss)		21,957			(3,749	)		(4,138	)		(4,443	)
Net income (loss) per share attributable to common shareholders—basic	$	1.61		$	(2.28	)	$	(0.23	)	$	(0.25	)
Net income (loss) per share attributable to common shareholders—diluted	$	1.45		$	(2.28	)	$	(0.23	)	$	(0.25	)

	2012 Quarter Ended
	December 31, 2011			March 31, 2012			June 30, 2012			September 30, 2012
Revenue	$	741		$	36,565		$	2,542		$	1,858
Operating expenses		3,923			4,470			6,070			5,954
Other income (expense), net		23			16			27			44
Net income (loss)		(3,159	)		32,111			(3,501	)		(4,052	)
Net income (loss) per share attributable to common shareholders—basic	$	(4.44	)	$	2.41		$	(4.31	)	$	(4.78	)
Net income (loss) per share attributable to common shareholders—diluted	$	(4.44	)	$	2.17		$	(4.31	)	$	(4.78	)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

Use of Estimates

Use of Estimates

Cash Equivalents and Marketable Securities

Cash Equivalents and Marketable Securities

Restricted Cash

Restricted Cash

Concentration of Credit Risk and of Significant Customers and Suppliers

Concentration of Credit Risk and of Significant Customers and Suppliers

Fair Value Measurements

Fair Value Measurements

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Property and Equipment

Property and Equipment


Laboratory and office equipment		3–5 years
Leasehold improvements		Shorter of life of lease or estimated useful life
Purchased software		3–5 years
Computer equipment		3–5 years
Furniture		7 years

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets

Revenue Recognition

Revenue Recognition

Research and Development Costs

Research and Development Costs

Patent Costs

Patent Costs

Deferred Offering Costs

Deferred Offering Costs

Accounting for Stock-Based Compensation

Accounting for Stock-Based Compensation

Income Taxes

Income Taxes

Net Income (Loss) Per Share

Net Income (Loss) Per Share

Segment Data

Segment Data

Comprehensive Income (Loss)

Comprehensive Income (Loss)

Recently Issued and Adopted Accounting Pronouncements

Recently Issued and Adopted Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Property and Equipment Estimated Useful Lives


Laboratory and office equipment		3–5 years
Leasehold improvements		Shorter of life of lease or estimated useful life
Purchased software		3–5 years
Computer equipment		3–5 years
Furniture		7 years

Fair Value of Financial Assets and Liabilities (Tables)

12 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities That Were Subject to Fair Value Measurement on Recurring Basis


	Fair Value Measurements as of September 30, 2013 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	7,517	$	—	$	—	$	7,517
U.S. Treasury notes		1,005		—		—		1,005
Commercial paper		—		10,596		—		10,596
Corporate bonds		—		84,755		—		84,755
U.S. Agency bonds		—		3,518		—		3,518
Certificate of deposit		—		3,450		—		3,450

	$	8,522	$	102,319	$	—	$	110,841

Liabilities:
Warrant liability	$	—	$	—	$	1,620	$	1,620

	$	—	$	—	$	1,620	$	1,620


	Fair Value Measurements as of September 30, 2012 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	6,471	$	—	$	—	$	6,471
U.S. Treasury notes		1,015		—		—		1,015
Commercial paper		—		8,143		—		8,143
Corporate bonds		—		25,749		—		25,749

	$	7,486	$	33,892	$	—	$	41,378

Liabilities:
Warrant liability	$	—	$	—	$	2,001	$	2,001

	$	—	$	—	$	2,001	$	2,001

Fair Value Measurements of the Company's Warrant Liability

The recurring Level 3 fair value measurements of the Company’s warrant liability using probability-weighted discounted cash flow include the following significant unobservable inputs:


	Unobservable Input	Range (Weighted Average)
Warrant Liability	Probabilities of payout	25% - 90%

	Periods in which payout is expected to occur	2014 - 2018

	Discount rate	4.25%

Rollforward of Aggregate Fair Values of Warrants


Balance, September 30, 2010	$	26
Warrants issued		1,280
Increase in fair value		705
Decrease in fair value		(18	)

Balance, September 30, 2011		1,993
Warrants expired		(8	)
Increase in fair value		19
Decrease in fair value		(3	)

Balance, September 30, 2012		2,001
Warrants expired		(20	)
Decrease in fair value		(361	)

Balance, September 30, 2013	$	1,620

Marketable Securities (Tables)

12 Months Ended

Sep. 30, 2013

Investments Debt And Equity Securities [Abstract]

Fair Value of Available-for-Sale Marketable Securities by Type of Security

As of September 30, 2013 and 2012, the fair value of available-for-sale marketable securities by type of security was as follows:


	September 30, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	10,596	$	—	$	—		$	10,596
Corporate bonds		84,757		23		(25	)		84,755
U.S. Agency bonds		3,519		—		(1	)		3,518
Certificate of deposit		3,450		—		—			3,450
U.S. Treasury notes		1,004		1		—			1,005

	$	103,326	$	24	$	(26	)	$	103,324


	September 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Commercial paper	$	8,143	$	—	$	—		$	8,143
Corporate bonds		25,741		9		(1	)		25,749
U.S. Treasury notes		1,013		2		—			1,015

	$	34,897	$	11	$	(1	)	$	34,907

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Property and Equipment (Tables)

12 Months Ended

Sep. 30, 2013

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consisted of the following as of September 30, 2013 and 2012:


	September 30,
	2013			2012
Laboratory and office equipment	$	4,395		$	4,142
Leasehold improvements		272			268
Purchased software		438			402
Computer equipment		90			76
Furniture		263			259

		5,458			5,147
Less: Accumulated depreciation and amortization		(4,337	)		(4,536	)

	$	1,121		$	611

Accrued Expenses and Other Long-Term Liabilities (Tables)

12 Months Ended

Sep. 30, 2013

Payables And Accruals [Abstract]

Accrued Expenses (Current) and Other Long-Term Liabilities

Accrued expenses (current) and other long-term liabilities consisted of the following as of September 30, 2013 and 2012:


	September 30,
	2013		2012
Accrued expenses:
Accrued payroll and related expenses	$	1,041	$	1,305
Accrued vendor manufacturing		989		1,330
Accrued professional fees		378		718
Accrued third-party license fee		240		222
Accrued other		387		291

	$	3,035	$	3,866

Other long-term liabilities:
Accrued rent expense	$	127	$	75
Present value of accrued third-party license fee		184		423
Asset retirement obligation		48		—

	$	359	$	498

Preferred Stock (Tables)

12 Months Ended

Sep. 30, 2013

Equity [Abstract]

Redeemable Convertible Preferred Stock

Redeemable convertible preferred stock consisted of the following as of September 30, 2012:


	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Liquidation Preference		Carrying Value		Common Stock Issuable Upon Conversion
Series C redeemable convertible preferred stock		2,543,603		2,543,603	$	8,551	$	8,551		590,159
Series D redeemable convertible preferred stock		5,968,334		5,968,334		37,922		37,922		1,853,953
Series E redeemable convertible preferred stock		16,132,546		14,368,037		66,136		66,136		4,386,373
Series F redeemable convertible preferred stock		6,894,966		6,894,966		15,000		15,000		1,599,760
Series G-1 redeemable convertible preferred stock		4,729,543		4,620,764		12,500		12,376		1,072,103
Series G-2 redeemable convertible preferred stock		9,152,296		8,719,639		18,970		18,970		2,023,110

		45,421,288		43,115,343	$	159,079	$	158,955		11,525,458

Schedule of Convertible Preferred Stock

Convertible preferred stock, which was not redeemable, consisted of the following as of September 30, 2012:


	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Liquidation Preference		Carrying Value		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		379,450		379,450	$	140	$	140		88,033
Series B convertible preferred stock		187,000		187,000		187		187		43,384

		566,450		566,450	$	327	$	327		131,417

Preferred Stock Warrants (Tables)

12 Months Ended

Sep. 30, 2013

Text Block [Abstract]

Summary of Warrant Activity

The following table summarizes the Company’s warrant activity since October 1, 2010:


	Common Stock Exercisable			Weighted Average Exercise Price		Series E Preferred Stock Exercisable			Weighted Average Exercise Price		Series 1 Preferred Stock Exercisable		Weighted Average Exercise Price
Outstanding, as of September 30, 2010		345,952		$	8.40		341,556		$	2.51		—
Granted		—					—					1,999,989
Expired		(345,952	)				—					—
Exercised		—					—					—

Outstanding, as of September 30, 2011		—					341,556		$	2.51		1,999,989	$	0.01
Granted		—					—					—
Expired		—					(329,056	)				—
Exercised		—					—					—

Outstanding, as of September 30, 2012		—					12,500		$	2.51		1,999,989	$	0.01
Granted		—					—					—
Expired		—					(12,500	)				—
Exercised		—					—					—

Outstanding, as of September 30, 2013		—					—					1,999,989	$	0.01

Stock-Based Awards (Tables)

12 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Data Used to Determine Value of Stock Option Grants, Presented on Weighted Average Basis

The relevant data used to determine the value of the stock option grants is as follows, presented on a weighted average basis:


	Year Ended September 30,
	2013			2012			2011
Risk-free interest rate		1.05	%		0.93	%		2.73	%
Expected term (in years)		6.09			6.00			6.25
Expected volatility		73	%		78	%		87	%
Expected dividend yield		0	%		0	%		0	%

Stock Option Activity

The following table summarizes stock option activity for the year ended September 30, 2013:


	Shares Issuable Under Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding as of September 30, 2012		1,771,471		$	2.08		4.1	$	19,911
Granted		364,318			14.21
Exercised		(538,575	)		1.04
Forfeited		(11,319	)		12.54
Expired		(2,864	)		2.59

Outstanding as of September 30, 2013		1,583,031		$	5.15		5.0	$	28,133

Options vested and expected to vest as of September 30, 2013		1,408,344		$	4.06		4.5	$	26,568

Options exercisable as of September 30, 2013		1,161,570		$	2.33		3.5	$	23,919

Stock-Based Compensation Expense

The Company recorded stock-based compensation expense for the years ended September 30, 2013, 2012 and 2011 in the following expense categories:


	Year Ended September 30,
	2013		2012		2011
Research and development	$	393	$	126	$	66
General and administrative		670		298		159

	$	1,063	$	424	$	225

Net Income (Loss) Per Share (Tables)

12 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders

Basic and diluted net income (loss) per share attributable to common stockholders was calculated as follows for the years ended September 30, 2013, 2012 and 2011:


	Year Ended September 30,
	2013			2012			2011
Basic net income (loss) per share attributable to common stockholders:
Numerator:
Net income	$	9,627		$	21,399		$	23,310
Accretion of redeemable convertible preferred stock to redemption value		(2,526	)		(5,367	)		(5,454	)
Net income attributable to participating securities		(13,670	)		(14,663	)		(16,291	)

Net income (loss) attributable to common stockholders	$	(6,569	)	$	1,369		$	1,565

Denominator:
Weighted average common shares outstanding—basic		9,788,039			1,088,784			1,119,250

Net income (loss) per share attributable to common stockholders—basic	$	(0.67	)	$	1.26		$	1.40


	Year Ended September 30,
	2013			2012			2011
Diluted net income (loss) per share attributable to common stockholders:
Numerator:
Net income	$	9,627		$	21,399		$	23,310
Accretion of redeemable convertible preferred stock to redemption value		(2,526	)		(5,367	)		(5,454	)
Net income attributable to participating securities		(13,670	)		(13,225	)		(15,401	)

Net income (loss) attributable to common stockholders—diluted	$	(6,569	)	$	2,807		$	2,455

Denominator:
Weighted average common shares outstanding—basic		9,788,039			1,088,784			1,119,250
Dilutive effect of common stock equivalents		—			1,386,039			738,023

Weighted average common shares outstanding—diluted		9,788,039			2,474,823			1,857,273

Net income (loss) per share attributable to common stockholders—diluted	$	(0.67	)	$	1.13		$	1.32

Commitments and Contingencies (Tables)

12 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Lease Payments For Operating Leases

Future minimum lease payments for operating leases as of September 30, 2013 are as follows:


Year ending September 30,
2014		921
2015		946
2016		972
2017		999
2018		1,027

Total	$	4,865

Future Non-Cancelable Minimum Payments

Future non-cancelable minimum payments under the agreement are as follows:


Year ending September 30,
2014		250
2015		200

Total	$	450

Income Taxes (Tables)

12 Months Ended

Sep. 30, 2013

Income Tax Disclosure [Abstract]

Reconciliation of Income Tax Provision at Federal Statutory Income Tax Rate and Effective Tax Rate

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:


	Year Ended September 30,
	2013			2012			2011
Federal statutory income tax rate		34.0	%		34.0	%		34.0	%
State taxes, net of federal benefit		5.5			5.4			5.8
Federal research and development tax credit		(2.5	)		(0.2	)		(2.0	)
Change in deferred tax asset valuation allowance		(51.0	)		(40.1	)		(40.5	)
Other		14.0			0.9			2.7

Effective income tax rate		0.0	%		0.0	%		0.0	%

Deferred Tax Assets and Liabilities

Net deferred tax assets as of September 30, 2013 and 2012 consisted of the following:


	September 30,
	2013			2012
Net operating loss carryforwards	$	8,495		$	10,961
Tax credit carryforwards		6,111			5,731
Capitalized research and development expenses		6,953			9,750
Other temporary differences		1,333			1,357

Gross deferred tax assets		22,892			27,799
Valuation allowance		(22,892	)		(27,799	)

Net deferred tax assets	$	—		$	—

Schedule of Deferred Tax Assets Valuation Allowance

Changes in the valuation allowance for deferred tax assets during the years ended September 30, 2013, 2012 and 2011 were as follows:


	Year Ended September 30,
	2013			2012			2011
Valuation allowance as of beginning of year	$	27,799		$	36,369		$	45,812
Decreases recorded as benefit to income tax provision		(4,907	)		(8,570	)		(9,443	)
Increases recorded to income tax provision		—			—			—

Valuation allowance as of end of year	$	22,892		$	27,799		$	36,369

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Sep. 30, 2013

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

Quarterly financial information for fiscal 2013 and 2012 is presented in the following table, in thousands, except per share data:


	2013 Quarter Ended
	December 31, 2012			March 31, 2013			June 30, 2013			September 30, 2013
Revenue	$	27,859		$	1,196		$	1,649		$	1,349
Operating expenses		5,950			5,197			5,827			6,050
Other income (expense), net		48			252			40			258
Net income (loss)		21,957			(3,749	)		(4,138	)		(4,443	)
Net income (loss) per share attributable to common shareholders—basic	$	1.61		$	(2.28	)	$	(0.23	)	$	(0.25	)
Net income (loss) per share attributable to common shareholders—diluted	$	1.45		$	(2.28	)	$	(0.23	)	$	(0.25	)

	2012 Quarter Ended
	December 31, 2011			March 31, 2012			June 30, 2012			September 30, 2012
Revenue	$	741		$	36,565		$	2,542		$	1,858
Operating expenses		3,923			4,470			6,070			5,954
Other income (expense), net		23			16			27			44
Net income (loss)		(3,159	)		32,111			(3,501	)		(4,052	)
Net income (loss) per share attributable to common shareholders—basic	$	(4.44	)	$	2.41		$	(4.31	)	$	(4.78	)
Net income (loss) per share attributable to common shareholders—diluted	$	(4.44	)	$	2.17		$	(4.31	)	$	(4.78	)

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Summary of Accounting and Financial Policies [Line Items]
Adjustment to fair value	$ 0	$ 0	$ 0
Cash and investment restricted as a collateral for outstanding letter of credit	436	436
Deferred financing costs		2,129
Money Market Funds [Member]
Summary of Accounting and Financial Policies [Line Items]
Cash and investment restricted as a collateral for outstanding letter of credit	$ 436	$ 436
Maximum [Member]
Summary of Accounting and Financial Policies [Line Items]
Short-term investments maturity period	Ninety days
Short-term marketable securities maturity period	1 year
Minimum [Member]
Summary of Accounting and Financial Policies [Line Items]
Short-term marketable securities maturity period	3 months
Long-term marketable securities maturity period	One year
Income tax benefit recognition, percentage of likelihood of being realized upon settlement	50.00%

Summary of Significant Accounting Policies - Property and Equipment Estimated Useful Lives (Detail)	12 Months Ended
	Sep. 30, 2013
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements useful life	Shorter of life of lease or estimated useful life
Minimum [Member] \| Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Minimum [Member] \| Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Minimum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Maximum [Member] \| Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	5 years
Maximum [Member] \| Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	5 years
Maximum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	5 years
Maximum [Member] \| Furniture [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	7 years

Fair Value of Financial Assets and Liabilities - Financial Assets and Liabilities That Were Subject to Fair Value Measurement on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Assets:
Cash equivalents	$ 7,517	$ 6,471
Available for sale securities, fair value	103,324	34,907
Assets, Fair Value Disclosure, Total	110,841	41,378
Liabilities:
Warrant liability	1,620	2,001
Liabilities, Fair Value Disclosure, Total	1,620	2,001
U.S. Treasury Notes [Member]
Assets:
Available for sale securities, fair value	1,005	1,015
Commercial Paper [Member]
Assets:
Available for sale securities, fair value	10,596	8,143
Corporate Bonds [Member]
Assets:
Available for sale securities, fair value	84,755	25,749
U.S. Agency Bonds [Member]
Assets:
Available for sale securities, fair value	3,518
Certificate of Deposit [Member]
Assets:
Available for sale securities, fair value	3,450
Level 1 [Member]
Assets:
Cash equivalents	7,517	6,471
Assets, Fair Value Disclosure, Total	8,522	7,486
Liabilities:
Warrant liability
Liabilities, Fair Value Disclosure, Total
Level 1 [Member] \| U.S. Treasury Notes [Member]
Assets:
Available for sale securities, fair value	1,005	1,015
Level 1 [Member] \| Commercial Paper [Member]
Assets:
Available for sale securities, fair value
Level 1 [Member] \| Corporate Bonds [Member]
Assets:
Available for sale securities, fair value
Level 1 [Member] \| U.S. Agency Bonds [Member]
Assets:
Available for sale securities, fair value
Level 1 [Member] \| Certificate of Deposit [Member]
Assets:
Available for sale securities, fair value
Level 2 [Member]
Assets:
Cash equivalents
Assets, Fair Value Disclosure, Total	102,319	33,892
Liabilities:
Warrant liability
Liabilities, Fair Value Disclosure, Total
Level 2 [Member] \| U.S. Treasury Notes [Member]
Assets:
Available for sale securities, fair value
Level 2 [Member] \| Commercial Paper [Member]
Assets:
Available for sale securities, fair value	10,596	8,143
Level 2 [Member] \| Corporate Bonds [Member]
Assets:
Available for sale securities, fair value	84,755	25,749
Level 2 [Member] \| U.S. Agency Bonds [Member]
Assets:
Available for sale securities, fair value	3,518
Level 2 [Member] \| Certificate of Deposit [Member]
Assets:
Available for sale securities, fair value	3,450
Level 3 [Member]
Assets:
Cash equivalents
Assets, Fair Value Disclosure, Total
Liabilities:
Warrant liability	1,620	2,001
Liabilities, Fair Value Disclosure, Total	1,620	2,001
Level 3 [Member] \| U.S. Treasury Notes [Member]
Assets:
Available for sale securities, fair value
Level 3 [Member] \| Commercial Paper [Member]
Assets:
Available for sale securities, fair value
Level 3 [Member] \| Corporate Bonds [Member]
Assets:
Available for sale securities, fair value
Level 3 [Member] \| U.S. Agency Bonds [Member]
Assets:
Available for sale securities, fair value
Level 3 [Member] \| Certificate of Deposit [Member]
Assets:
Available for sale securities, fair value

Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0	$ 0
Fair value of warrants				$ 1,280
Series 1 Nonconvertible Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants	$ 1,620	1,981
Series E Redeemable Convertible Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of warrants		$ 20

Fair Value of Financial Assets and Liabilities - Fair Value Measurements of the Company's Warrant Liability (Detail) - Warrant Liability [Member]	12 Months Ended
	Sep. 30, 2013
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount rate	4.25%
Minimum [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probabilities of payout	25.00%
Periods in which payout is expected to occur	2014
Maximum [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Probabilities of payout	90.00%
Periods in which payout is expected to occur	2018

Fair Value of Financial Assets and Liabilities - Rollforward of Aggregate Fair Values of Warrants (Detail) - Warrant Liability [Member] - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Fair Value, Instruments Classified in Shareholders' Equity Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 2,001	$ 1,993	$ 26
Warrants expired	(20)	(8)
Warrants issued			1,280
Increase in fair value		19	705
Decrease in fair value	(361)	(3)	(18)
Ending Balance	$ 1,620	$ 2,001	$ 1,993

Marketable Securities - Fair Value of Available-for-Sale Marketable Securities by Type of Security (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 103,326	$ 34,897
Gross Unrealized Gains	24	11
Gross Unrealized Losses	(26)	(1)
Fair Value	103,324	34,907
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,596	8,143
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	10,596	8,143
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	84,757	25,741
Gross Unrealized Gains	23	9
Gross Unrealized Losses	(25)	(1)
Fair Value	84,755	25,749
U.S. Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,519
Gross Unrealized Gains
Gross Unrealized Losses	(1)
Fair Value	3,518
Certificate of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,450
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	3,450
U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,004	1,013
Gross Unrealized Gains	1	2
Gross Unrealized Losses
Fair Value	$ 1,005	$ 1,015

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Marketable securities maturing within two years, aggregate fair value	$ 10,703	$ 1,656
Short Term Marketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	Within one year	Within one year
Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	Within two years	Within two years

Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Property, Plant and Equipment [Line Items]
Property and equipment	$ 5,458	$ 5,147
Less: Accumulated depreciation and amortization	(4,337)	(4,536)
Property and equipment, net	1,121	611
Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	4,395	4,142
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	272	268
Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	438	402
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	90	76
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 263	$ 259

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property Plant And Equipment Useful Life And Values [Abstract]
Depreciation and amortization expense	$ 221	$ 172	$ 499
Cost of assets sold	420	273	3,810
Gain of assets sold	$ 100	$ 63	$ 7

Accrued Expenses and Other Long-Term Liabilities - Accrued Expenses (Current) and Other Long-Term Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Accrued expenses:
Accrued payroll and related expenses	$ 1,041	$ 1,305
Accrued vendor manufacturing	989	1,330
Accrued professional fees	378	718
Accrued third-party license fee	240	222
Accrued other	387	291
Accrued expenses	3,035	3,866
Other long-term liabilities:
Accrued rent expense	127	75
Present value of accrued third-party license fee	184	423
Asset retirement obligation	48
Other long-term liabilities	$ 359	$ 498

Convertible Notes - Additional Information (Detail) $ in Thousands	1 Months Ended		12 Months Ended
	Dec. 31, 2010 USD ($) shares	Oct. 31, 2010 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2013 USD ($) $ / Warrant	Nov. 30, 2010 USD ($)
Debt Instrument [Line Items]
Aggregate principal amount of term notes to be issued		$ 6,500
Interest rate on term notes		5.00%
Maturity date of principal and interest		Oct. 04, 2011
Prepayment premium on term note		51.80%
Company borrowings					$ 2,000
Balance not drawn down					$ 4,500
Debt discount and derivative liability				$ 670
Exercise price of warrants \| $ / Warrant				0.01
Total fair value at date of issuance	$ 1,280
Total fair value	1,983
Milestone payment	40,000
Company repayment in principal plus	2,000		$ 2,000
Accrued interest paid	20
Premium applicable	1,036
Issuance costs incurred			$ 41
Total deferred financing costs	$ 150
Nonconvertible Preferred Shares [Member]
Debt Instrument [Line Items]
Number of shares issuable \| shares	1,999,989

Collaboration Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended									12 Months Ended
	Sep. 30, 2013 USD ($)	Mar. 31, 2013	Mar. 26, 2013 $ / shares shares	Nov. 30, 2012 USD ($)	Mar. 31, 2012 USD ($)	Feb. 16, 2012 USD ($)	Dec. 31, 2010 USD ($)	Nov. 30, 2006 USD ($)	Nov. 27, 2006 USD ($) $ / shares shares	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($) Renewals	Sep. 30, 2010 USD ($)	Aug. 31, 2013 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Issuance of Series G-1 redeemable convertible preferred stock \| shares			4,600,000
Price of Series G-1 redeemable convertible preferred stock \| $ / shares			$ 14.00
Milestone revenue payments received							$ 40,000
Revenue invoiced but unpaid	$ 808									$ 808	$ 1,049
Revenue unpaid and included in unbilled receivables	784									784	1,893
Abbvie [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment under the agreement								$ 48,300
Collaboration Agreement Tiered Royalty Description								From the low double digits up to twenty percent, or up to the high teens on a blended basis, on net sales
Additional payment for research services										4,150
Milestone revenue payments received										$ 15,000	0	$ 41,882	$ 6,518
Proceed received to fund research activities	107,450
Delivering period under the AbbVie Agreement										3 years
Agreement continuation period										10 years
Abbvie [Member] \| Series G-1 Redeemable Convertible Preferred Stock [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Issuance of Series G-1 redeemable convertible preferred stock \| shares									4,620,764
Price of Series G-1 redeemable convertible preferred stock \| $ / shares									$ 2.70518
Gross proceeds from issuance of Series G-1 redeemable convertible preferred stock									$ 12,500
Premium on Series G-1 redeemable convertible preferred stock									$ 1,617
Abbvie [Member] \| Regulatory Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected proceed from milestone payment										$ 40,000
Abbvie [Member] \| Commercial Milestone Payments [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected proceed from milestone payment										155,000
Abbvie [Member] \| Phase 2 Clinical Trial [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue payments received							$ 40,000
Abbvie [Member] \| Additional Funding Agreement Terms [Member] \| Commercial Milestone Payments [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected proceed from milestone payment										80,000
Abbvie [Member] \| Phase 3 Clinical Trial [Member] \| Milestone Payments [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue payments received										15,000
Novartis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration Agreement Tiered Royalty Description						From the low double digits up to the high teens on net product sales
Milestone revenue payments received										$ 12,675	35,567
Agreement continuation period										10 years
Revenue from upfront cash payment					$ 34,442
Amount attributable to license fees										$ 10,894
Amount attributable to the performance of research service										$ 1,781
Agreement termination period										120 days
Novartis [Member] \| Phase 2 Clinical Trial [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected proceed from milestone payment						$ 15,000
Novartis [Member] \| Quality Assurance and Testing [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected Nonrefundable upfront fee and reimbursement expense						$ 34,442
Novartis [Member] \| Phase 1 Clinical Trial [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone revenue payments received				$ 11,000
Novartis [Member] \| Research Contracts [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research funding period						1 year
Additional research funding period		6 months
Novartis [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total of additional milestone payments						$ 395,000
Novartis [Member] \| Maximum [Member] \| Research Contracts [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected proceed from milestone payment						$ 1,800
National Institutes of Health, National Institute of Allergy and Infectious Diseases [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Awarded contract for development, Contract period												5 years
Awarded contract for development, number of extension option \| Renewals												6
Extended expiration date												September 30, 2016
Additional fund for preclinical and early clinical development														$ 9,200
Total funding paid or committed for preclinical and early clinical development														$ 23,500
Revenue from grants										$ 4,378	6,139
Revenue invoiced but unpaid	258									258	1,049
Revenue unpaid and included in unbilled receivables	$ 784									$ 784	$ 1,668
National Institutes of Health, National Institute of Allergy and Infectious Diseases [Member] \| Initial [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Awarded contract for development, amount												$ 14,300
Awarded contract for development, Contract period												30 months
Expiration date												Mar. 30, 2014
National Institutes of Health, National Institute of Allergy and Infectious Diseases [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Awarded contract for development, amount												$ 42,700
National Institutes of Health, National Institute of Allergy and Infectious Diseases [Member] \| Maximum [Member] \| Initial [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Awarded contract for development, amount												$ 42,700

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Mar. 26, 2013 USD ($) $ / shares shares	Mar. 21, 2013 shares	Mar. 01, 2013	Sep. 30, 2013 USD ($) shares	Sep. 30, 2011 shares	Mar. 31, 2013 shares	Sep. 30, 2012 shares	Feb. 29, 2012 shares
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock, shares authorized				100,000,000		100,000,000	100,000,000	70,000,000
Reverse stock split ratio			4.31
Shares issued in initial public offering	4,600,000
Net proceeds from initial public offering \| $	$ 59,892			$ 59,892
Shares issued, price per share \| $ / shares	$ 14.00
Restricted common stock that were forfeited by former employees					208,816
Conversion of Redeemable Convertible Preferred Stock and Convertible Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Shares of common stock issued upon conversion of preferred stock		11,656,875

Preferred Stock - Redeemable Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		2,543,603
Preferred Shares Issued and Outstanding		2,543,603
Liquidation Preference		$ 8,551
Carrying Value		$ 8,551
Common stock Issuable Upon Conversion		590,159
Series D- Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		5,968,334
Preferred Shares Issued and Outstanding		5,968,334
Liquidation Preference		$ 37,922
Carrying Value		$ 37,922
Common stock Issuable Upon Conversion		1,853,953
Series E Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		16,132,546
Preferred Shares Issued and Outstanding		14,368,037
Liquidation Preference		$ 66,136
Carrying Value		$ 66,136
Common stock Issuable Upon Conversion		4,386,373
Series F Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		6,894,966
Preferred Shares Issued and Outstanding		6,894,966
Liquidation Preference		$ 15,000
Carrying Value		$ 15,000
Common stock Issuable Upon Conversion		1,599,760
Series G-1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		4,729,543
Preferred Shares Issued and Outstanding		4,620,764
Liquidation Preference		$ 12,500
Carrying Value		$ 12,376
Common stock Issuable Upon Conversion		1,072,103
Series G-2 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		9,152,296
Preferred Shares Issued and Outstanding		8,719,639
Liquidation Preference		$ 18,970
Carrying Value		$ 18,970
Common stock Issuable Upon Conversion		2,023,110
Series C, D, E, F, G-1 and G-2 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		45,421,288
Preferred Shares Issued and Outstanding		43,115,343
Liquidation Preference		$ 159,079
Carrying Value		$ 158,955
Common stock Issuable Upon Conversion		11,525,458

Preferred Stock - Additional Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2013 USD ($) $ / shares shares	Sep. 30, 2012 USD ($) shares	Sep. 30, 2011 USD ($)
Temporary Equity [Line Items]
Dividends Declared \| $	$ 0
Cumulative dividends and accretion to redemption value \| $	$ (2,526)	$ (5,367)	$ (5,454)
Percentage of voting right held	80.00%
Redeemable Preferred Stock Conversion Basis	0.23202
Initial public offering closing date	Mar. 26, 2013
Series C, D, E, F, G-1 and G-2 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Common stock shares \| shares	11,525,458
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	7.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 1.72
Conversion ratio of Redeemable Preferred Stock into common stock	1.72
Conversion price of Redeemable Preferred Stock into common stock	$ 7.41320
Redeemable Preferred Stock Conversion Basis	0.23202
Series D- Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	9.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 3.00
Conversion ratio of Redeemable Preferred Stock into common stock	3.00
Conversion price of Redeemable Preferred Stock into common stock	$ 9.65772
Redeemable Preferred Stock Conversion Basis	0.31063
Series E Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	9.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 2.51
Conversion ratio of Redeemable Preferred Stock into common stock	2.51
Conversion price of Redeemable Preferred Stock into common stock	$ 8.22176
Redeemable Preferred Stock Conversion Basis	0.30529
Series F Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	7.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 2.1755
Conversion ratio of Redeemable Preferred Stock into common stock	2.1755
Conversion price of Redeemable Preferred Stock into common stock	$ 9.37641
Redeemable Preferred Stock Conversion Basis	0.23202
Series G-1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	7.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 2.70518
Conversion ratio of Redeemable Preferred Stock into common stock	2.70518
Conversion price of Redeemable Preferred Stock into common stock	$ 11.65933
Redeemable Preferred Stock Conversion Basis	0.23202
Series G-2 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Percentage of dividends to Redeemable convertible preferred stockholders	7.00%
Conversion ratio of Redeemable Preferred Stock into common stock	$ 2.1755
Conversion ratio of Redeemable Preferred Stock into common stock	2.1755
Conversion price of Redeemable Preferred Stock into common stock	$ 9.37641
Redeemable Preferred Stock Conversion Basis	0.23202
Series A and B Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Common stock shares \| shares	131,417
Series A Convertible Preferred Stock[Member]
Temporary Equity [Line Items]
Conversion ratio of Redeemable Preferred Stock into common stock	$ 0.37
Series B Convertible Preferred Stock[Member]
Temporary Equity [Line Items]
Conversion ratio of Redeemable Preferred Stock into common stock	$ 1.00
Series 1 Nonconvertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares authorized \| shares	1,999,989
Par value of outstanding convertible preferred stock	$ 0.01
Preferred shares issued or outstanding \| shares	0	0
Preferred shares outstanding \| shares	0	0
Per share value adjusted for stock dividend	$ 1.00
Preferred stock redemption price per share	$ 1.00
Redemption period	60 days
Aggregate liquidation preference \| $	$ 2,000

Preferred Stock - Schedule of Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012
Series A Convertible Preferred Stock[Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		379,450
Preferred Shares Issued and Outstanding		379,450
Liquidation Preference		$ 140
Carrying Value		$ 140
Common stock Issuable Upon Conversion		88,033
Series B Convertible Preferred Stock[Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		187,000
Preferred Shares Issued and Outstanding		187,000
Liquidation Preference		$ 187
Carrying Value		$ 187
Common stock Issuable Upon Conversion		43,384
Series A and B Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		566,450
Preferred Shares Issued and Outstanding		566,450
Liquidation Preference		$ 327
Carrying Value		$ 327
Common stock Issuable Upon Conversion		131,417

Common Stock Warrants - Additional Information (Detail) - shares	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Common Stock [Member]
Common Stock Warrants [Line Items]
Common Stock Warrants Outstanding				345,952

Preferred Stock Warrants - Additional Information (Detail) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Nov. 30, 2010	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Class of Stock [Line Items]
Fair value of warrants					$ 1,280
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Warrant for the purchase of series E preferred stock outstanding			12,500	341,556		341,556
Warrant for the purchase of shares expired		12,500	329,056
Warrants expired		12,500
Change in fair value of the warrants			$ 19	$ (18)
Income expense related to warrant expiration		$ 20	8
Warrant fair value			20
Series 1 Nonconvertible Preferred Stock [Member]
Class of Stock [Line Items]
Change in fair value of the warrants		(361)	(3)
Number of shares issuable upon exercise of the warrants	1,999,989
Warrant expiration date	Oct. 04, 2017
Fair value of warrants	$ 1,280	$ 1,620	$ 1,981

Preferred Stock Warrants - Summary of Warrant Activity (Detail) - $ / shares	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Common Stock [Member]
Preferred Stock And Warrant [Line Items]
Beginning Balance			345,952
Granted
Expired			(345,952)
Exercised
Ending Balance
Weighted Average Exercise Price Outstanding, Beginning Balance			$ 8.40
Weighted Average Exercise Price Outstanding, Ending Balance
Series E Preferred Stock [Member]
Preferred Stock And Warrant [Line Items]
Beginning Balance	12,500	341,556	341,556
Granted
Expired	(12,500)	(329,056)
Exercised
Ending Balance		12,500	341,556
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 2.51	$ 2.51	$ 2.51
Weighted Average Exercise Price Outstanding, Ending Balance		$ 2.51	$ 2.51
Series 1 Preferred Stock [Member]
Preferred Stock And Warrant [Line Items]
Beginning Balance	1,999,989	1,999,989
Granted			1,999,989
Expired
Exercised
Ending Balance	1,999,989	1,999,989	1,999,989
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 0.01	$ 0.01
Weighted Average Exercise Price Outstanding, Ending Balance	$ 0.01	$ 0.01	$ 0.01

Stock-Based Awards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Jan. 17, 2013	Jan. 03, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares issued		18,138,597	1,343,147
Shares of common stock		17,929,781	1,134,331
Options granted to executives		364,318
Aggregate intrinsic value of stock options exercised		$ 7,574	$ 606	$ 10
Cash proceeds from exercise of stock options		$ 559	$ 141	$ 34
Weighted average grant date fair value of option granted		$ 9.16	$ 7.79	$ 1.95
Aggregate of unrecognized stock-based compensation cost		$ 1,416
Weighted average recognition period		2 years 9 months 18 days
2012 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares issued		321,613
Percentage of outstanding shares of common stock		3.00%
Shares of common stock		2,088,167
2012 Equity Incentive Plan [Member] \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted to executives	167,052
Fair value of options at the grant date	$ 1,487
Stock based compensation, expenses		$ 0
1995 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting percentage		25.00%
Options granted, expiration period		10 years
Common stock shares issued		2,540,759			2,772,777
Shares available for future grant		346,038
Common stock reserved						185,614
Shares issued under the ESPP		0
Period for service based award		4 years
1995 Equity Incentive Plan [Member] \| Executive Officer [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting period		1 year
1995 Equity Incentive Plan [Member] \| Executive Officer [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting period		4 years
1995 Equity Incentive Plan [Member] \| Board of Directors [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting period		2 years
1995 Equity Incentive Plan [Member] \| Board of Directors [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, vesting period		3 years

Stock-Based Awards - Data Used to Determine Value of Stock Option Grants, Presented on Weighted Average Basis (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	1.05%	0.93%	2.73%
Expected term (in years)	6 years 1 month 2 days	6 years	6 years 3 months
Expected volatility	73.00%	78.00%	87.00%
Expected dividend yield	0.00%	0.00%	0.00%

Stock-Based Awards - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Shares Issuable Under Options
Outstanding as of beginning of period	1,771,471
Granted	364,318
Exercised	(538,575)
Forfeited	(11,319)
Expired	(2,864)
Outstanding as of end of period	1,583,031	1,771,471
Options vested and expected to vest as of end of period	1,408,344
Options exercisable as of end of period	1,161,570
Weighted Average Exercise Price
Outstanding as of beginning of period	$ 2.08
Granted	14.21
Exercised	1.04
Forfeited	12.54
Expired	2.59
Outstanding as of ending balance	5.15	$ 2.08
Options vested and expected to vest as of end of period	4.06
Options exercisable as of end of period	$ 2.33
Weighted Average Remaining Contractual Term (In years)
Outstanding as of end of period	5 years	4 years 1 month 6 days
Options vested and expected to vest as of end period	4 years 6 months
Options exercisable as of end of period	3 years 6 months
Aggregate Intrinsic Value
Outstanding as of beginning of period	$ 19,911
Outstanding as of end of period	28,133	$ 19,911
Options vested and expected to vest as of end of period	26,568
Options exercisable as of end of period	$ 23,919

Stock-Based Awards - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,063	$ 424	$ 225
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	393	126	66
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 670	$ 298	$ 159

Net Income (Loss) Per Share - Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Basic net income (loss) per share attributable to common stockholders:
Net income	$ (4,443)	$ (4,138)	$ (3,749)	$ 21,957	$ (4,052)	$ (3,501)	$ 32,111	$ (3,159)	$ 9,627	$ 21,399	$ 23,310
Accretion of redeemable convertible preferred stock to redemption value									(2,526)	(5,367)	(5,454)
Net income attributable to participating securities									(13,670)	(14,663)	(16,291)
Net income (loss) attributable to common stockholders									$ (6,569)	$ 1,369	$ 1,565
Weighted average common shares outstanding-basic									9,788,039	1,088,784	1,119,250
Net income (loss) per share attributable to common stockholders-basic	$ (0.25)	$ (0.23)	$ (2.28)	$ 1.61	$ (4.78)	$ (4.31)	$ 2.41	$ (4.44)	$ (0.67)	$ 1.26	$ 1.40
Diluted net income (loss) per share attributable to common stockholders:
Net income	$ (4,443)	$ (4,138)	$ (3,749)	$ 21,957	$ (4,052)	$ (3,501)	$ 32,111	$ (3,159)	$ 9,627	$ 21,399	$ 23,310
Accretion of redeemable convertible preferred stock to redemption value									(2,526)	(5,367)	(5,454)
Net income attributable to participating securities									(13,670)	(13,225)	(15,401)
Net income (loss) attributable to common stockholders-diluted									$ (6,569)	$ 2,807	$ 2,455
Weighted average common shares outstanding-basic									9,788,039	1,088,784	1,119,250
Dilutive effect of common stock equivalents										1,386,039	738,023
Weighted average common shares outstanding-diluted									9,788,039	2,474,823	1,857,273
Net income (loss) per share attributable to common stockholders-diluted	$ (0.25)	$ (0.23)	$ (2.28)	$ 1.45	$ (4.78)	$ (4.31)	$ 2.17	$ (4.44)	$ (0.67)	$ 1.13	$ 1.32

Net Income (Loss) Per Share - Additional Information (Detail) - shares	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted net income per share	1,713,313	33,359	594,453
Warrant Liability [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted net income per share			341,556

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Nov. 30, 2011
Commitments And Contingencies [Line Items]
Lease for new office space Duration	7 years		10 years
Rent expense	$ 948	$ 948	$ 1,995
Office lease expiration period	September 2011
Outstanding letter of credit	$ 436			$ 1,140
Restricted cash	436	436
Upfront license fees payable		350
License expense		895
Maintenance fees	105
One-time fee	50
License agreement, recorded liability	6,505	8,233
License agreement, recorded liability	1,481	1,851
License agreement, recorded liability	3,035	3,866
Upfront license fees paid	350
Company's obligation to pay	5,000
Payment for license agreement	500
License Agreement Terms [Member]
Commitments And Contingencies [Line Items]
License agreement, recorded liability	674	995
License agreement, recorded liability	250	350
License agreement, recorded liability	240	222
License agreement, recorded liability	184	$ 423
First Anniversary [Member]
Commitments And Contingencies [Line Items]
License expense	250
Second Anniversary [Member]
Commitments And Contingencies [Line Items]
License expense	250
Third Anniversary [Member]
Commitments And Contingencies [Line Items]
License expense	$ 200

Commitments and Contingencies - Future Minimum Lease Payments for Operating Leases (Detail) $ in Thousands	Sep. 30, 2013 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2014	$ 921
2015	946
2016	972
2017	999
2018	1,027
Total	$ 4,865

Commitments and Contingencies - Future Non-cancelable Minimum Payments under the Agreement (Detail) $ in Thousands	Sep. 30, 2013 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2014	$ 250
2015	200
Total	$ 450

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax [Line Items]
Provision for Income Tax	$ 0	$ 0	$ 0
Income before income taxes	9,627	21,399	$ 21,310
Unrecognized Tax Benefits	0	$ 0
Federal[Member]
Income Tax [Line Items]
Net operating loss carryforwards	24,107
Research and development tax credit carryforwards	$ 4,375
Net operating loss carryforwards begin to expire	2018
Research and development tax credit carryforwards begin to expire	2021
State[Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 5,653
Research and development tax credit carryforwards	$ 2,631
Net operating loss carryforwards begin to expire	2015
Research and development tax credit carryforwards begin to expire	2016

Income Taxes - Reconciliation of Income Tax Provision at Federal Statutory Income Tax Rate and Effective Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	5.50%	5.40%	5.80%
Federal research and development tax credit	(2.50%)	(0.20%)	(2.00%)
Change in deferred tax asset valuation allowance	(51.00%)	(40.10%)	(40.50%)
Other	14.00%	0.90%	2.70%
Effective income tax rate	0.00%	0.00%	0.00%

Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 8,495	$ 10,961
Tax credit carryforwards	6,111	5,731
Capitalized research and development expenses	6,953	9,750
Other temporary differences	1,333	1,357
Gross deferred tax assets	22,892	27,799
Valuation allowance	(22,892)	(27,799)	$ (36,369)	$ (45,812)
Net deferred tax assets

Income Taxes - Schedule of Deferred Tax Assets Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Valuation allowance as of beginning of year	$ 27,799	$ 36,369	$ 45,812
Decreases recorded as benefit to income tax provision	(4,907)	(8,570)	(9,443)
Increases recorded to income tax provision
Valuation allowance as of end of year	$ 22,892	$ 27,799	$ 36,369

401(k) Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Compensation Related Costs [Abstract]
Percentage of annual contribution	2.00%
Annual base salary of employee	$ 4
Benefits charged to operating expenses	$ 90	$ 84	$ 95

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Director [Member]
Schedule of Other Related Party Transactions [Line Items]
Consulting fees expensed and paid	$ 10	$ 75	$ 75

Qualifying Therapeutic Discovery Project Program - Additional Information (Detail) - Qualifying Therapeutic Discovery Project Program [Member] $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2010 USD ($) Project	Sep. 30, 2011 USD ($) Project	Sep. 30, 2010 Project	Oct. 31, 2011 USD ($)
Qualifying Therapeutic Discovery Project Program [Line Items]
Number of projects for grants \| Project	4
Percentage of Project Credit program	50.00%
Project Credit program expense	$ 244
Proceeds from project grants		$ 750
Project grant revenue		489
Project grant receivable		$ 261		$ 261
Number of projects carried out during period \| Project		2	2

Selected Quarterly Financial Data - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,349	$ 1,649	$ 1,196	$ 27,859	$ 1,858	$ 2,542	$ 36,565	$ 741	$ 32,053	$ 41,706	$ 41,882
Operating expenses	6,050	5,827	5,197	5,950	5,954	6,070	4,470	3,923	23,024	20,417	16,583
Other income (expense), net	258	40	252	48	44	27	16	23			355
Net income (loss)	$ (4,443)	$ (4,138)	$ (3,749)	$ 21,957	$ (4,052)	$ (3,501)	$ 32,111	$ (3,159)	$ 9,627	$ 21,399	$ 23,310
Net income (loss) per share attributable to common shareholders-basic	$ (0.25)	$ (0.23)	$ (2.28)	$ 1.61	$ (4.78)	$ (4.31)	$ 2.41	$ (4.44)	$ (0.67)	$ 1.26	$ 1.40
Net income (loss) per share attributable to common shareholders-diluted	$ (0.25)	$ (0.23)	$ (2.28)	$ 1.45	$ (4.78)	$ (4.31)	$ 2.17	$ (4.44)	$ (0.67)	$ 1.13	$ 1.32

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details