0000950170-23-019842 | 10-Q | XBRL Viewer | Enanta Pharmaceuticals INC

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Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Current assets:
Cash and cash equivalents	$ 73,178	$ 43,994
Short-term marketable securities	136,906	205,238
Accounts receivable	17,795	20,318
Prepaid expenses and other current assets	14,484	13,445
Income tax receivable	28,774	28,718
Total current assets	271,137	311,713
Long-term marketable securities	15,040	29,285
Property and equipment, net	11,050	6,173
Operating lease, right-of-use assets	24,554	23,575
Restricted cash	3,968	3,968
Other long-term assets	696	696
Total assets	326,445	375,410
Current liabilities:
Accounts payable	11,761	6,000
Accrued expenses and other current liabilities	15,482	20,936
Operating lease liabilities	4,923	2,891
Total current liabilities	32,166	29,827
Operating lease liabilities, net of current portion	23,073	22,372
Series 1 nonconvertible preferred stock	1,423	1,423
Other long-term liabilities	408	454
Total liabilities	57,070	54,076
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock; $0.01 par value per share, 100,000 shares authorized; 21,049 and 20,791 shares issued and outstanding at March 31, 2023 and September 30, 2022, respectively	210	208
Additional paid-in capital	410,803	398,029
Accumulated other comprehensive loss	(1,815)	(3,724)
Accumulated deficit	(139,823)	(73,179)
Total stockholders' equity	269,375	321,334
Total liabilities and stockholders' equity	$ 326,445	$ 375,410

Fair Value of Financial Assets and Liabilities - Fair Value Measurements of the Company's Outstanding Series 1 Nonconvertible Preferred Stock (Detail) - Level 3 [Member] - Series 1 Nonconvertible Preferred Stock [Member]	Mar. 31, 2023	Sep. 30, 2022
Probabilities of Payout [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range	0	0
Probabilities of Payout [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range	65	65
Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range	7.25	7.25

Stock-Based Awards - Summary of PSUs and rTSRUs Activity (Detail) shares in Thousands	6 Months Ended
	Mar. 31, 2023 $ / shares shares
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance \| shares	101
Granted \| shares	50
Vested \| shares	(70)
Unvested, ending balance \| shares	81
Weighted Average Grant Date Fair Value, Unvested beginning balance \| $ / shares	$ 54.50
Weighted Average Grant Date Fair Value, Granted \| $ / shares	47.24
Weighted Average Grant Date Fair Value, Vested \| $ / shares	44.58
Weighted Average Grant Date Fair Value, Unvested ending balance \| $ / shares	$ 58.58
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance \| shares	101
Granted \| shares	50
Vested \| shares	(70)
Unvested, ending balance \| shares	81
Weighted Average Grant Date Fair Value, Unvested beginning balance \| $ / shares	$ 36.14
Weighted Average Grant Date Fair Value, Granted \| $ / shares	36.91
Weighted Average Grant Date Fair Value, Vested \| $ / shares	23.89
Weighted Average Grant Date Fair Value, Unvested ending balance \| $ / shares	$ 45.82

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Mar. 31, 2023	Apr. 28, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Trading Symbol	ENTA
Entity Registrant Name	ENANTA PHARMACEUTICALS, INC
Entity Central Index Key	0001177648
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-35839
Security Exchange Name	NASDAQ
Entity Tax Identification Number	04-3205099
Entity Address, Address Line One	500 Arsenal Street
Entity Address, City or Town	Watertown
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02472
City Area Code	617
Title of 12(b) Security	Common Stock, par value $0.01 per share
Local Phone Number	607-0800
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		21,055,392

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Total revenue	$ 17,795	$ 18,716	$ 41,380	$ 46,364
Operating expenses:
Research and development	43,468	42,087	84,370	90,636
General and administrative	13,778	10,476	26,474	19,984
Total operating expenses	57,246	52,563	110,844	110,620
Loss from operations	(39,451)	(33,847)	(69,464)	(64,256)
Other income (expense):
Interest and investment income, net	1,837	255	2,830	549
Total other income, net	1,837	255	2,830	549
Loss before income taxes	(37,614)	(33,592)	(66,634)	(63,707)
Income tax expense	(44)	0	(10)	0
Net loss	$ (37,658)	$ (33,592)	$ (66,644)	$ (63,707)
Net loss per share:
Basic	$ (1.79)	$ (1.63)	$ (3.19)	$ (3.11)
Diluted	$ (1.79)	$ (1.63)	$ (3.19)	$ (3.11)
Weighted average shares outstanding:
Basic	21,035	20,551	20,882	20,473
Diluted	21,035	20,551	20,882	20,473
Royalty [Member]
Total revenue	$ 17,795	$ 18,716	$ 40,380	$ 46,364
License [Member]
Total revenue	$ 0	$ 0	$ 1,000	$ 0

Marketable Securities - Fair Value of Available-for-Sale Marketable Securities by Type of Security (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 153,377	$ 237,863
Gross Unrealized Gains	18	0
Gross Unrealized Losses	(1,449)	(3,340)
Fair Value	151,946	234,523
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	47,329	78,663
Gross Unrealized Gains	4	0
Gross Unrealized Losses	(1,209)	(2,252)
Fair Value	46,124	76,411
U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,229	92,416
Gross Unrealized Gains	14	0
Gross Unrealized Losses	(240)	(1,088)
Fair Value	22,003	91,328
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	83,819	66,784
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 83,819	$ 66,784

Subsequent Events - Additional Information (Detail) - Subsequent Event [Member] $ in Thousands	1 Months Ended
	Apr. 30, 2023 USD ($)
Subsequent Event [Line Items]
Future quarterly royalty payments, cash received	$ 200,000
OCM Life Sciences Portfolio LP [Member]
Subsequent Event [Line Items]
Future quarterly royalty payments, cash received	$ 200,000
Future quarterly royalty payments, description	beginning with the payment for the quarter ending September 30, 2023, through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price.
Percentage of future quarterly royalty payments on net sales received in cash	54.50%

Stock-Based Awards

6 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Awards

8. Stock-Based Awards

The Company grants stock-based awards, including stock options, restricted stock units and other unit awards under its 2019 Equity Incentive Plan (the “2019 Plan”), which was approved by its stockholders on February 28, 2019 and amended in March 2021, March 2022 and March 2023. The Company also has outstanding stock option awards under its 2012 Equity Incentive Plan (the “2012 Plan”) and its amended and restated 1995 Equity Incentive Plan (the “1995 Plan”), but is no longer granting awards under these plans.

The following table summarizes stock option activity, including performance-based options, for the year-to-date period ending March 31, 2023:


	Shares Issuable Under Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	(in thousands)					(in years)		(in thousands)
Outstanding as of September 30, 2022		3,993		$	53.57		6.2	$	28,778
Granted		728			45.44
Exercised		(117	)		17.14
Forfeited		(82	)		65.95
Outstanding as of March 31, 2023		4,522		$	52.98		6.5	$	7,572
Options vested and expected to vest as of March 31, 2023		4,522		$	52.98		6.5	$	7,572
Options exercisable as of March 31, 2023		2,801		$	51.94		5.0	$	7,554

Market and Performance-Based Stock Unit Awards

The Company awards both performance share units, or PSUs, and relative total stockholder return units, or rTSRUs, to its executive officers. The number of units granted represents the target number of shares of common stock that may be earned; however, the actual number of shares that may be earned ranges from 0% to 150% of the target number. The number of shares cancelled represents the target number of shares, less any shares that vested. The following table summarizes PSU and rTSRU activity for the year-to-date period ending March 31, 2023:


	PSUs					rTSRUs
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
	(in thousands, except per share data)
Unvested at September 30, 2022		101		$	54.50		101		$	36.14
Granted		50			47.24		50			36.91
Vested		(70	)		44.58		(70	)		23.89
Cancelled		—			—		—			—
Unvested at March 31, 2023		81		$	58.58		81		$	45.82

During the six months ended March 31, 2023, a total of 100% of the target PSUs and 127% of the target rTSRUs granted in December 2020 vested, resulting in the issuance of an aggregate of 104 common shares, net of share withholding.

Restricted Stock Units

The following table summarizes the restricted stock unit activity for the year-to-date period ending March 31, 2023:


	Restricted Stock Units			Weighted Average Grant Date Fair Value
	(in thousands, except per share data)
Unvested at September 30, 2022		219		$	64.03
Granted		277			45.00
Vested		(56	)		61.10
Cancelled		(10	)		54.51
Unvested at March 31, 2023		430		$	52.37

Stock-Based Compensation Expense

During the three and six months ended March 31, 2023 and 2022 the Company recognized the following stock-based compensation expense:



	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
	(in thousands)
Research and development	$	2,520	$	2,710	$	5,052	$	5,294
General and administrative		4,843		3,761		9,450		7,239
	$	7,363	$	6,471	$	14,502	$	12,533



	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
	(in thousands)
Stock options	$	5,011	$	4,962	$	10,057	$	9,710
rTSRUs		546		531		1,007		823
Performance stock units		175		79		542		512
Restricted stock units		1,631		899		2,896		1,488
	$	7,363	$	6,471	$	14,502	$	12,533

During the three and six months ended March 31, 2023 and 2022, the Company recognized stock-based compensation expense for performance-based stock units for which vesting became probable upon achievement of performance-based targets that occurred during the performance period.

As of March 31, 2023, the Company had an aggregate of $70,253 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.6 years.

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended
	Apr. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
Entity incorporated, in year						1995
Net loss		$ 37,658	$ 28,986	$ 33,592	$ 30,115	$ 66,644	$ 63,707	$ 121,755
Accumulated deficit		139,823				139,823		$ 73,179
Cash, cash equivalents and short-term and long-term marketable securities		$ 225,124				$ 225,124
Subsequent Event [Member]
Payment received royalty purchase agreement	$ 200,000
OCM Life Sciences Portfolio LP [Member] \| Subsequent Event [Member]
Payment received royalty purchase agreement	$ 200,000

- Definition

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

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+ Details

Stock-Based Awards (Tables)

6 Months Ended

Mar. 31, 2023

Summary of Stock Option Activity Including Performance Based Options

The following table summarizes stock option activity, including performance-based options, for the year-to-date period ending March 31, 2023:


	Shares Issuable Under Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	(in thousands)					(in years)		(in thousands)
Outstanding as of September 30, 2022		3,993		$	53.57		6.2	$	28,778
Granted		728			45.44
Exercised		(117	)		17.14
Forfeited		(82	)		65.95
Outstanding as of March 31, 2023		4,522		$	52.98		6.5	$	7,572
Options vested and expected to vest as of March 31, 2023		4,522		$	52.98		6.5	$	7,572
Options exercisable as of March 31, 2023		2,801		$	51.94		5.0	$	7,554

Summary of Restricted Stock Unit Activity

The following table summarizes the restricted stock unit activity for the year-to-date period ending March 31, 2023:


	Restricted Stock Units			Weighted Average Grant Date Fair Value
	(in thousands, except per share data)
Unvested at September 30, 2022		219		$	64.03
Granted		277			45.00
Vested		(56	)		61.10
Cancelled		(10	)		54.51
Unvested at March 31, 2023		430		$	52.37

Stock-Based Compensation Expense

During the three and six months ended March 31, 2023 and 2022 the Company recognized the following stock-based compensation expense:



	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
	(in thousands)
Research and development	$	2,520	$	2,710	$	5,052	$	5,294
General and administrative		4,843		3,761		9,450		7,239
	$	7,363	$	6,471	$	14,502	$	12,533



	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
	(in thousands)
Stock options	$	5,011	$	4,962	$	10,057	$	9,710
rTSRUs		546		531		1,007		823
Performance stock units		175		79		542		512
Restricted stock units		1,631		899		2,896		1,488
	$	7,363	$	6,471	$	14,502	$	12,533

Performance Share Units and Relative Total Stockholder Return Units [Member]

Summary of PSUs and rTSRUs Activity

The following table summarizes PSU and rTSRU activity for the year-to-date period ending March 31, 2023:


	PSUs					rTSRUs
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
	(in thousands, except per share data)
Unvested at September 30, 2022		101		$	54.50		101		$	36.14
Granted		50			47.24		50			36.91
Vested		(70	)		44.58		(70	)		23.89
Cancelled		—			—		—			—
Unvested at March 31, 2023		81		$	58.58		81		$	45.82

Subsequent Events	6 Months Ended
Subsequent Events	Mar. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In April 2023, the Company entered into a royalty sale agreement with an affiliate of OMERS, pursuant to which the Company was paid a $200,000 cash purchase price in exchange for 54.5% of the Company’s future quarterly royalty payments on net sales of MAVYRET/MAVIRET, beginning with the payment for the quarter ending September 30, 2023, through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price.

Commitments and Contingencies

6 Months Ended

Mar. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

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. For example, 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, would 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.

On June 21, 2022, the Company filed suit in the United States District Court for the District of Massachusetts, against Pfizer, Inc. seeking damages for infringement of U.S. Patent No. 11,358,953 (the ’953 Patent) in the manufacture, use and sale of Pfizer’s COVID-19 antiviral, Paxlovid™ (nirmatrelvir tablets; ritonavir tablets). The United States Patent and Trademark Office awarded the '953 Patent to the Company in June 2022 based on the Company's July 2020 patent application describing coronavirus protease inhibitors invented by the Company. The Company is seeking fair compensation for Pfizer’s use of a coronavirus protease inhibitor

claimed in the ‘953 patent. The Company records all legal expenses associated with the patent infringement suit as incurred in the consolidated statements of operations.

The Company currently is not a party to any other litigation.

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 or from services to be provided to 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 and its executive officers 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 directors’ and officers’ 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 has not accrued any liabilities related to such obligations in its consolidated financial statements as of March 31, 2023.

Leases

The Company leases office space under various non-cancelable operating leases. There have been no material changes to the Company’s leases during the three and six months ended March 31, 2023. For additional information, please read Note 11, Leases, to the consolidated financial statements in the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2022.

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities
Net loss	$ (66,644)	$ (63,707)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	14,502	12,533
Depreciation and amortization expense	1,051	1,602
Premium paid on marketable securities	(42)	(802)
Amortization (accretion) of premiums (discounts) on marketable securities	(1,345)	928
Loss on disposal of property and equipment	7	0
Change in operating assets and liabilities:
Accounts receivable	2,523	4,860
Prepaid expenses and other current assets	(1,039)	110
Income tax receivable	(56)	8,507
Operating lease, right-of-use assets	1,891	2,784
Accounts payable	5,963	(3,473)
Accrued expenses	(6,052)	(808)
Operating lease liabilities	(137)	(2,498)
Other long-term liabilities	(46)	318
Net cash used in operating activities	(49,424)	(39,646)
Cash flows from investing activities
Purchase of marketable securities	(90,627)	(124,631)
Proceeds from maturities and sales of marketable securities	176,500	135,514
Purchase of property and equipment	(5,539)	(437)
Net cash provided by investing activities	80,334	10,446
Cash flows from financing activities
Proceeds from exercise of stock options	2,008	14,211
Payments for settlement of share-based awards	(3,734)	(1,228)
Net cash provided by (used in) financing activities	(1,726)	12,983
Net increase (decrease) in cash, cash equivalents and restricted cash	29,184	(16,217)
Cash, cash equivalents and restricted cash at beginning of period	47,962	57,814
Cash, cash equivalents and restricted cash at end of period	77,146	41,597
Supplemental disclosure of noncash information:
Purchases of fixed assets included in accounts payable and accrued expenses	1,611	174
Operating lease liabilities arising from obtaining right-of-use assets	$ 2,870	$ 15,559

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Schedule of Available-for-sale Securities [Line Items]
Long-term marketable securities	$ 15,040	$ 29,285
Maximum [Member] \| Short Term Marketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	1 year
Long Term Marketable Securities [Member] \| Maximum [Member] \| Corporate Bonds and U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	2 years
Long Term Marketable Securities [Member] \| Minimum [Member] \| Corporate Bonds and U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	1 year

Series 1 Nonconvertible Preferred Stock - Additional Information (Detail) - Series 1 Nonconvertible Preferred Stock [Member]	Mar. 31, 2023 shares
Class Of Stock [Line Items]
Preferred stock, shares issued	1,930,000
Preferred stock, shares outstanding	1,930,000

Stock-Based Awards - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands	6 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period	2020-12
Common Stock, Shares, Issued	21,049	20,791
Aggregate of unrecognized stock-based compensation cost	$ 70,253
Weighted average recognition period	2 years 7 months 6 days
Relative Total Stockholder Return Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	127.00%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	100.00%
Executive Officers [Member] \| Relative Total Stockholder Return Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares range percentage	0.00%
Number of shares range percentage	150.00%

Fair Value of Financial Assets and Liabilities

6 Months Ended

Mar. 31, 2023

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 March 31, 2023 and September 30, 2022, and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value:


	Fair Value Measurements at March 31, 2023 Using:
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Cash equivalents:
Money market funds	$	70,562	$	—	$	—	$	70,562
Marketable securities:
U.S. Treasury notes		22,003		—		—		22,003
Corporate bonds		—		46,124		—		46,124
Commercial paper		—		83,819		—		83,819
	$	92,565	$	129,943	$	—	$	222,508
Liabilities:
Series 1 nonconvertible preferred stock	$	—	$	—	$	1,423	$	1,423
	$	—	$	—	$	1,423	$	1,423


	Fair Value Measurements at September 30, 2022 Using:
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Cash equivalents:
Money market funds	$	13,905	$	—	$	—	$	13,905
Marketable securities:
U.S. Treasury notes		91,328		—		—		91,328
Corporate bonds		—		76,411		—		76,411
Commercial paper		—		66,784		—		66,784
	$	105,233	$	143,195	$	—	$	248,428
Liabilities:
Series 1 nonconvertible preferred stock	$	—	$	—	$	1,423	$	1,423
	$	—	$	—	$	1,423	$	1,423

During the three and six months ended March 31, 2023 and 2022, there were no transfers between Level 1, Level 2 and Level 3.

The outstanding shares of Series 1 nonconvertible preferred stock as of March 31, 2023 and September 30, 2022 are measured at fair value. These outstanding shares are financial instruments that might require a transfer of assets because of the liquidation features in the contract and are therefore recorded as liabilities and measured at fair value. The fair value of the outstanding shares is based on significant inputs not observable in the market, which represent a Level 3 measurement within the fair value hierarchy. The Company utilizes a probability-weighted valuation model which takes into consideration various outcomes that may require the Company to transfer assets upon liquidation. Changes in the fair values of the Series 1 nonconvertible preferred stock are recognized in other income (expense) in the consolidated statements of operations.

The recurring Level 3 fair value measurements of the Company’s outstanding Series 1 nonconvertible preferred stock using probability-weighted discounted cash flow include the following significant unobservable inputs:


	Range
	March 31,	September 30,
Unobservable Input	2023	2022
Probabilities of payout	0%-65%	0%-65%
Discount rate	7.25%	7.25%

There were no changes in the fair value of nonconvertible preferred stock during the three and six months ended March 31, 2023 or 2022.

- 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

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (37,658)	$ (33,592)	$ (66,644)	$ (63,707)
Other comprehensive income (loss):
Net unrealized gains (losses) on marketable securities	860	(2,031)	1,909	(2,655)
Total other comprehensive income (loss)	860	(2,031)	1,909	(2,655)
Comprehensive loss	$ (36,798)	$ (35,623)	$ (64,735)	$ (66,362)

- Definition

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

+ References

+ Details

Marketable Securities (Tables)

6 Months Ended

Mar. 31, 2023

Investments, Debt and Equity Securities [Abstract]

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

As of March 31, 2023 and September 30, 2022, the fair value of available-for-sale marketable securities, by type of security, was as follows:


	March 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Corporate bonds	$	47,329	$	4	$	(1,209	)	$	—	$	46,124
Commercial paper		83,819		—		—			—		83,819
U.S. Treasury notes		22,229		14		(240	)		—		22,003
	$	153,377	$	18	$	(1,449	)	$	—	$	151,946


	September 30, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Corporate bonds	$	78,663	$	—	$	(2,252	)	$	—	$	76,411
Commercial paper		66,784		—		—			—		66,784
U.S. Treasury notes		92,416		—		(1,088	)		—		91,328
	$	237,863	$	—	$	(3,340	)	$	—	$	234,523

AbbVie Collaboration

6 Months Ended

Mar. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

AbbVie Collaboration

6. AbbVie Collaboration

The Company has a Collaborative Development and License Agreement (as amended, the “AbbVie Agreement”), with AbbVie to identify, develop and commercialize HCV NS3 and NS3/4A protease inhibitor compounds, including paritaprevir and glecaprevir, under which the Company has received license payments, proceeds from a sale of preferred stock, research funding payments, milestone payments and royalties totaling approximately $1,250,000 through March 31, 2023.

The Company is receiving annually tiered royalties per Company protease product ranging from ten percent up to twenty percent, or on a blended basis from ten percent up to the high teens, on the portion of AbbVie’s calendar year net sales of each HCV regimen that is allocated to the protease inhibitor in the regimen. Beginning with each January 1, the cumulative net sales of a given royalty-bearing protease inhibitor product start at zero for purposes of calculating the tiered royalties on a product-by-product basis.

Summary of Significant Accounting Policies - Diluted Net Loss Per Share Attributable to Common Stockholders With Anti-dilutive effect (Detail) - shares shares in Thousands	6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,522	4,124
Unvested rTSRUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	81	112
Unvested PSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	81	112
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	430	217

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	(Accumulated Deficit) Retained Earnings [Member]
Beginning Balance at Sep. 30, 2021	$ 399,429	$ 202	$ 351,033	$ (382)	$ 48,576
Beginning Balance, Shares at Sep. 30, 2021		20,238,000
Exercise of stock options	10,409	$ 2	10,407
Exercise of stock options, Shares		248,000
Vesting of restricted stock units, net of withholding	(777)	$ 1	(778)
Vesting of restricted stock units, net of withholding, Shares		20,000
Stock-based compensation expense	6,062		6,062
Other comprehensive (loss) income	(624)			(624)
Net loss	(30,115)				(30,115)
Ending Balance at Dec. 31, 2021	384,384	$ 205	366,724	(1,006)	18,461
Ending Balance, Shares at Dec. 31, 2021		20,506,000
Beginning Balance at Sep. 30, 2021	399,429	$ 202	351,033	(382)	48,576
Beginning Balance, Shares at Sep. 30, 2021		20,238,000
Other comprehensive (loss) income	(2,655)
Net loss	(63,707)
Ending Balance at Mar. 31, 2022	358,583	$ 206	376,545	(3,037)	(15,131)
Ending Balance, Shares at Mar. 31, 2022		20,618,000
Beginning Balance at Sep. 30, 2021	399,429	$ 202	351,033	(382)	48,576
Beginning Balance, Shares at Sep. 30, 2021		20,238,000
Net loss	(121,755)
Ending Balance at Sep. 30, 2022	321,334	$ 208	398,029	(3,724)	(73,179)
Ending Balance, Shares at Sep. 30, 2022		20,791,000
Beginning Balance at Dec. 31, 2021	384,384	$ 205	366,724	(1,006)	18,461
Beginning Balance, Shares at Dec. 31, 2021		20,506,000
Exercise of stock options	3,802	$ 1	3,801
Exercise of stock options, Shares		97,000
Vesting of restricted stock units, net of withholding	(451)		(451)
Vesting of restricted stock units, net of withholding, Shares		15,000
Stock-based compensation expense	6,471		6,471
Other comprehensive (loss) income	(2,031)			(2,031)
Net loss	(33,592)				(33,592)
Ending Balance at Mar. 31, 2022	358,583	$ 206	376,545	(3,037)	(15,131)
Ending Balance, Shares at Mar. 31, 2022		20,618,000
Beginning Balance at Sep. 30, 2022	321,334	$ 208	398,029	(3,724)	(73,179)
Beginning Balance, Shares at Sep. 30, 2022		20,791,000
Exercise of stock options	1,126	$ 1	1,125
Exercise of stock options, Shares		56,000
Vesting of restricted stock units, net of withholding	(825)		(825)
Vesting of restricted stock units, net of withholding, Shares		37,000
Stock-based compensation expense	7,139		7,139
Other comprehensive (loss) income	1,049			1,049
Net loss	(28,986)				(28,986)
Ending Balance at Dec. 31, 2022	300,837	$ 209	405,468	(2,675)	(102,165)
Ending Balance, Shares at Dec. 31, 2022		20,884,000
Beginning Balance at Sep. 30, 2022	$ 321,334	$ 208	398,029	(3,724)	(73,179)
Beginning Balance, Shares at Sep. 30, 2022		20,791,000
Exercise of stock options, Shares	117,000
Other comprehensive (loss) income	$ 1,909
Net loss	(66,644)
Ending Balance at Mar. 31, 2023	269,375	$ 210	410,803	(1,815)	(139,823)
Ending Balance, Shares at Mar. 31, 2023		21,049,000
Beginning Balance at Dec. 31, 2022	300,837	$ 209	405,468	(2,675)	(102,165)
Beginning Balance, Shares at Dec. 31, 2022		20,884,000
Exercise of stock options	882	$ 1	881
Exercise of stock options, Shares		61,000
Vesting of restricted stock units, net of withholding	(2,909)		(2,909)
Vesting of restricted stock units, net of withholding, Shares		104,000
Stock-based compensation expense	7,363		7,363
Other comprehensive (loss) income	860			860
Net loss	(37,658)				(37,658)
Ending Balance at Mar. 31, 2023	$ 269,375	$ 210	$ 410,803	$ (1,815)	$ (139,823)
Ending Balance, Shares at Mar. 31, 2023		21,049,000

- Definition

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

+ References

+ Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
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-Name Accounting Standards Codification
-Topic 852
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-SubTopic 10
-Section S99
-Paragraph 2
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section S99
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-Section S99
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-Subparagraph (SX 210.5-02(29))
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-Topic 825
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-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Nature of the Business and Basis of Presentation

6 Months Ended

Mar. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Enanta Pharmaceuticals, Inc. (the “Company”), incorporated in Delaware in 1995, is a biotechnology company that uses its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs, with an emphasis on treatments for viral infections. The Company discovered glecaprevir, the second of two protease inhibitors discovered and developed through its collaboration with AbbVie for the treatment of chronic infection with hepatitis C virus (“HCV”). Glecaprevir is co-formulated as part of AbbVie’s leading direct-acting antiviral (“DAA”) combination treatment for HCV, which is marketed under the tradenames MAVYRET® (U.S.) and MAVIRET®(ex-U.S.) (glecaprevir/pibrentasvir). Royalties from the Company’s AbbVie collaboration and its existing financial resources provide funding to support the Company’s wholly-owned research and development programs, which are primarily focused on the following disease targets: respiratory syncytial virus (“RSV”), SARS-CoV-2, human metapneumovirus (“hMPV”) and hepatitis B virus (“HBV”).

The Company is subject to many of the risks common to companies in the biotechnology industry, including but not limited to, the uncertainties of research and development, competition from technological innovations of others, dependence on collaborative arrangements, protection of proprietary technology, dependence on key personnel and compliance with government regulation. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approvals, prior to commercialization. These efforts require significant amounts of capital, adequate personnel and infrastructure, and extensive compliance reporting capabilities.

COVID-19

In March 2020, the World Health Organization declared COVID-19 a global pandemic and countries worldwide implemented various measures to contain the spread of the SARS-CoV-2 virus. National, state and local governments in affected regions implemented varying safety precautions, including quarantines, border closures, increased border controls, travel restrictions, shelter-in-place orders and shutdowns, business closures, cancellations of public gatherings and other measures. The extent and severity of any continuing impact on the Company’s business and clinical trials will be determined largely by the extent to which there are disruptions in the supply chains for its research and product candidates, delays in the conduct of ongoing and future clinical trials, or reductions in the number of patients accessing AbbVie’s HCV regimens, or any combination of those events. In addition, AbbVie experienced a decline in HCV sales compared to periods prior to March 2020 as a result of reduced numbers of patients accessing AbbVie’s HCV regimens due to the COVID-19 pandemic.

The extent to which the COVID-19 pandemic will continue to impact, directly or indirectly, the Company’s business, results of operations and financial condition will depend on future developments that are highly uncertain and cannot be accurately predicted, including new variants and public health actions taken to contain their impact, as well as the cumulative economic impact of both of those factors and the public health impact of the announced ending of emergency public health measures.

Unaudited Interim Financial Information

The consolidated balance sheet at September 30, 2022 was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America (“GAAP”). The accompanying unaudited consolidated financial statements as of March 31, 2023 and for the three and six months ended March 31, 2023 and 2022 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2022.

In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of March 31, 2023 and results of operations for the three and six months ended March 31, 2023 and 2022 and cash flows for the six months ended March 31, 2023 and 2022 have been made. The results of operations for the three and six months ended March 31, 2023 are not necessarily indicative of the results of operations that may be expected for subsequent quarters or the year ending September 30, 2023.

The accompanying consolidated financial statements have been prepared in conformity with GAAP. All amounts in the consolidated financial statements and in the notes to the consolidated financial statements, except per share amounts, are in thousands unless otherwise indicated.

The accompanying consolidated financial statements have been prepared based on continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company began reporting a net loss in fiscal 2020 and reported a net loss of $66,644 for the six months ended March 31, 2023 and $121,755 for the year ended September 30, 2022. As of March 31, 2023, the Company had an accumulated deficit of $139,823. The Company expects to continue to generate operating losses for the foreseeable future as the Company continues to advance its wholly-owned programs. As of March 31, 2023, the Company had $225,124 in cash, cash equivalents and short-term and long-term marketable securities. The Company expects that its cash, cash equivalents, short-term and long-term marketable securities, as well as the $200,000 payment received in April 2023 from the sale of a portion of the MAVYRET/MAVIRET royalties and cash flows from the continuing portion of HCV royalties will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of the interim consolidated financial statements. The Company may seek additional funding through equity offerings, non-dilutive financings, collaborations, strategic alliances or licensing agreements. The Company may not be able to obtain sufficient financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs, product expansion or commercialization efforts, or the Company may be unable to continue operations.

Series 1 Nonconvertible Preferred Stock

6 Months Ended

Mar. 31, 2023

Debt Disclosure [Abstract]

Series 1 Nonconvertible Preferred Stock

7. Series 1 Nonconvertible Preferred Stock

As of March 31, 2023, 1,930 shares of Series 1 nonconvertible preferred stock were issued and outstanding. Since these shares qualify as a derivative, the outstanding shares are carried at fair value as a liability on the Company’s consolidated balance sheets.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Mar. 31, 2023

Accounting Policies [Abstract]

Use of Estimates

The preparation of consolidated 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 consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, management’s judgments with respect to its revenue arrangements; valuation of stock-based awards and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. The future developments of the COVID-19 pandemic also may directly or indirectly impact the Company’s business. The Company has made estimates of the impact of COVID-19 in the Company’s consolidated financial statements as of March 31, 2023. Actual results could differ from the Company’s estimates.

Net Income (Loss) per Share

Basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) 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 unvested restricted stock units. For periods presented, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

The Company reported net losses for each of the three and six months ended March 31, 2023 and 2022. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:


	As of March 31,
	2023		2022
	(in thousands)
Options to purchase common stock		4,522		4,124
Unvested rTSRUs		81		112
Unvested PSUs		81		112
Unvested restricted stock units		430		217

Recently Issued Accounting Pronouncements

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 consolidated financial statements upon adoption.

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2023	Sep. 30, 2022
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	21,049	20,791
Common stock, shares outstanding	21,049	20,791

AbbVie Collaboration - Additional Information (Detail) - AbbVie [Member]	6 Months Ended
	Mar. 31, 2023 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash consideration received under collaboration from milestone payments and royalties	$ 1,250,000
Collaboration agreement tiered royalty description	from ten percent up to twenty percent, or on a blended basis from ten percent up to the high teens, on the portion of AbbVie’s calendar year net sales

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	Mar. 31, 2023	Sep. 30, 2022
Assets:
Marketable securities	$ 151,946	$ 234,523
Assets, Fair Value Disclosure, Total	222,508	248,428
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,423	1,423
Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,423	1,423
Level 1 [Member]
Assets:
Assets, Fair Value Disclosure, Total	92,565	105,233
Liabilities:
Liabilities, Fair Value Disclosure, Total	0	0
Level 1 [Member] \| Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	0	0
Level 2 [Member]
Assets:
Assets, Fair Value Disclosure, Total	129,943	143,195
Liabilities:
Liabilities, Fair Value Disclosure, Total	0	0
Level 2 [Member] \| Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	0	0
Level 3 [Member]
Assets:
Assets, Fair Value Disclosure, Total	0	0
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,423	1,423
Level 3 [Member] \| Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,423	1,423
U.S. Treasury Notes [Member]
Assets:
Marketable securities	22,003	91,328
U.S. Treasury Notes [Member] \| Level 1 [Member]
Assets:
Marketable securities	22,003	91,328
U.S. Treasury Notes [Member] \| Level 2 [Member]
Assets:
Marketable securities	0	0
U.S. Treasury Notes [Member] \| Level 3 [Member]
Assets:
Marketable securities	0	0
Corporate Bonds [Member]
Assets:
Marketable securities	46,124	76,411
Corporate Bonds [Member] \| Level 1 [Member]
Assets:
Marketable securities	0	0
Corporate Bonds [Member] \| Level 2 [Member]
Assets:
Marketable securities	46,124	76,411
Corporate Bonds [Member] \| Level 3 [Member]
Assets:
Marketable securities	0	0
Commercial Paper [Member]
Assets:
Marketable securities	83,819	66,784
Commercial Paper [Member] \| Level 1 [Member]
Assets:
Marketable securities	0	0
Commercial Paper [Member] \| Level 2 [Member]
Assets:
Marketable securities	83,819	66,784
Commercial Paper [Member] \| Level 3 [Member]
Assets:
Marketable securities	0	0
Money Market Funds [Member]
Assets:
Cash equivalents	70,562	13,905
Money Market Funds [Member] \| Level 1 [Member]
Assets:
Cash equivalents	70,562	13,905
Money Market Funds [Member] \| Level 2 [Member]
Assets:
Cash equivalents	0	0
Money Market Funds [Member] \| Level 3 [Member]
Assets:
Cash equivalents	$ 0	$ 0

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Mar. 31, 2023

Accounting Policies [Abstract]

Diluted Net Loss Per Share With Anti-dilutive effect

The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:


	As of March 31,
	2023		2022
	(in thousands)
Options to purchase common stock		4,522		4,124
Unvested rTSRUs		81		112
Unvested PSUs		81		112
Unvested restricted stock units		430		217

Marketable Securities

6 Months Ended

Mar. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

4. Marketable Securities

As of March 31, 2023 and September 30, 2022, the fair value of available-for-sale marketable securities, by type of security, was as follows:


	March 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Corporate bonds	$	47,329	$	4	$	(1,209	)	$	—	$	46,124
Commercial paper		83,819		—		—			—		83,819
U.S. Treasury notes		22,229		14		(240	)		—		22,003
	$	153,377	$	18	$	(1,449	)	$	—	$	151,946


	September 30, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Corporate bonds	$	78,663	$	—	$	(2,252	)	$	—	$	76,411
Commercial paper		66,784		—		—			—		66,784
U.S. Treasury notes		92,416		—		(1,088	)		—		91,328
	$	237,863	$	—	$	(3,340	)	$	—	$	234,523

As of March 31, 2023 and September 30, 2022, marketable securities consisted of investments that mature within one year, with the exception of certain corporate bonds and U.S. Treasury notes, which have maturities between one and two years and an aggregate fair value of $15,040 and $29,285, respectively.

Accrued Expenses (Tables)

6 Months Ended

Mar. 31, 2023

Payables and Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of March 31, 2023 and September 30, 2022:


	March 31,		September 30,
	2023		2022
	(in thousands)
Accrued pharmaceutical drug manufacturing	$	4,521	$	6,932
Accrued research and development expenses		5,380		5,532
Accrued payroll and related expenses		3,075		6,439
Accrued professional fees		1,639		1,273
Accrued other		867		760
	$	15,482	$	20,936

Accrued Expenses - Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Accrued expenses:
Accrued pharmaceutical drug manufacturing	$ 4,521	$ 6,932
Accrued research and development expenses	5,380	5,532
Accrued payroll and related expenses	3,075	6,439
Accrued professional fees	1,639	1,273
Accrued other	867	760
Accrued expenses	$ 15,482	$ 20,936

Stock-Based Awards - Summary of Stock Option Activity Including Performance Based Options (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares	Sep. 30, 2022 USD ($) $ / shares shares
Options
Outstanding as of beginning of period \| shares	3,993
Granted \| shares	728
Exercised \| shares	(117)
Forfeited \| shares	(82)
Outstanding as of end of period \| shares	4,522	3,993
Options vested and expected to vest as of end of period \| shares	4,522
Options exercisable as of end of period \| shares	2,801
Weighted Average Exercise Price
Outstanding \| $ / shares	$ 53.57
Granted \| $ / shares	45.44
Exercised \| $ / shares	17.14
Forfeited \| $ / shares	65.95
Outstanding \| $ / shares	52.98	$ 53.57
Options vested and expected to vest as of end of period \| $ / shares	52.98
Options exercisable as of end of period \| $ / shares	$ 51.94
Weighted Average Remaining Contractual Term
Outstanding as of end of period	6 years 6 months	6 years 2 months 12 days
Options vested and expected to vest as of end period	6 years 6 months
Options exercisable as of end of period	5 years
Aggregate Intrinsic Value
Aggregate Intrinsic Value \| $	$ 7,572	$ 28,778
Options vested and expected to vest as of December 31, 2021 \| $	7,572
Options exercisable as of end of period \| $	$ 7,554

Stock-Based Awards - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member] shares in Thousands	6 Months Ended
	Mar. 31, 2023 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance \| shares	219
Granted \| shares	277
Vested \| shares	(56)
Cancelled \| shares	(10)
Unvested, ending balance \| shares	430
Weighted Average Grant Date Fair Value, Unvested beginning balance \| $ / shares	$ 64.03
Weighted Average Grant Date Fair Value, Granted \| $ / shares	45.00
Weighted Average Grant Date Fair Value, Vested \| $ / shares	61.10
Weighted Average Grant Date Fair Value, Cancelled \| $ / shares	54.51
Weighted Average Grant Date Fair Value, Unvested ending balance \| $ / shares	$ 52.37

Accrued Expenses

6 Months Ended

Mar. 31, 2023

Payables and Accruals [Abstract]

Accrued Expenses

5. Accrued Expenses

Accrued expenses and other current liabilities consisted of the following as of March 31, 2023 and September 30, 2022:


	March 31,		September 30,
	2023		2022
	(in thousands)
Accrued pharmaceutical drug manufacturing	$	4,521	$	6,932
Accrued research and development expenses		5,380		5,532
Accrued payroll and related expenses		3,075		6,439
Accrued professional fees		1,639		1,273
Accrued other		867		760
	$	15,482	$	20,936

Stock-Based Awards - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 7,363	$ 6,471	$ 14,502	$ 12,533
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	5,011	4,962	10,057	9,710
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	546	531	1,007	823
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	175	79	542	512
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,631	899	2,896	1,488
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	2,520	2,710	5,052	5,294
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 4,843	$ 3,761	$ 9,450	$ 7,239

Summary of Significant Accounting Policies

6 Months Ended

Mar. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

For the Company’s Significant Accounting Policies, please refer to its Annual Report on Form 10-K for the fiscal year ended September 30, 2022. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Use of Estimates

Net Income (Loss) per Share


	As of March 31,
	2023		2022
	(in thousands)
Options to purchase common stock		4,522		4,124
Unvested rTSRUs		81		112
Unvested PSUs		81		112
Unvested restricted stock units		430		217

Recently Issued Accounting Pronouncements

Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0	$ 0	$ 0
Series 1 Nonconvertible Preferred Stock [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of nonconvertible preferred stock	$ 0	$ 0	$ 0	$ 0

Fair Value of Financial Assets and Liabilities (Tables)

6 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities that were Subject to Fair Value Measurement on Recurring Basis


	Fair Value Measurements at March 31, 2023 Using:
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Cash equivalents:
Money market funds	$	70,562	$	—	$	—	$	70,562
Marketable securities:
U.S. Treasury notes		22,003		—		—		22,003
Corporate bonds		—		46,124		—		46,124
Commercial paper		—		83,819		—		83,819
	$	92,565	$	129,943	$	—	$	222,508
Liabilities:
Series 1 nonconvertible preferred stock	$	—	$	—	$	1,423	$	1,423
	$	—	$	—	$	1,423	$	1,423


	Fair Value Measurements at September 30, 2022 Using:
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Cash equivalents:
Money market funds	$	13,905	$	—	$	—	$	13,905
Marketable securities:
U.S. Treasury notes		91,328		—		—		91,328
Corporate bonds		—		76,411		—		76,411
Commercial paper		—		66,784		—		66,784
	$	105,233	$	143,195	$	—	$	248,428
Liabilities:
Series 1 nonconvertible preferred stock	$	—	$	—	$	1,423	$	1,423
	$	—	$	—	$	1,423	$	1,423

Fair Value Measurements of the Company's Outstanding Series 1 Nonconvertible Preferred Stock


	Range
	March 31,	September 30,
Unobservable Input	2023	2022
Probabilities of payout	0%-65%	0%-65%
Discount rate	7.25%	7.25%