Enanta Pharmaceuticals (ENTA) 10-Q 11 May 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
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		20,004,258

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Current assets:
Cash and cash equivalents	$ 74,338	$ 51,230
Short-term marketable securities	280,917	284,006
Accounts receivable	27,619	51,313
Prepaid expenses and other current assets	19,835	15,299
Total current assets	402,709	401,848
Long-term marketable securities	80,099	65,013
Property and equipment, net	9,738	10,927
Deferred tax assets	12,418	11,341
Operating lease, right-of-use assets	7,837
Restricted cash	608	608
Other long-term assets	92	92
Total assets	513,501	489,829
Current liabilities:
Accounts payable	5,945	6,689
Accrued expenses and other current liabilities	9,807	15,920
Operating lease liabilities	3,764
Total current liabilities	19,516	22,609
Operating lease liabilities, net of current portion	5,330
Series 1 nonconvertible preferred stock	1,628	1,628
Other long-term liabilities	1,036	3,100
Total liabilities	27,510	27,337
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock; $0.01 par value per share, 100,000 shares authorized; 19,986 and 19,703 shares issued and outstanding at March 31, 2020 and September 30, 2019, respectively	200	197
Additional paid-in capital	314,005	298,409
Accumulated other comprehensive income	608	146
Retained earnings	171,178	163,740
Total stockholders' equity	485,991	462,492
Total liabilities and stockholders' equity	$ 513,501	$ 489,829

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Sep. 30, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	19,986,000	19,703,000
Common stock, shares outstanding	19,986,000	19,703,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Royalty revenue	$ 27,619	$ 39,631	$ 80,189	$ 109,517
Type Of Revenue Extensible List	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember
Operating expenses:
Research and development	$ 32,610	$ 34,155	$ 65,388	$ 69,033
General and administrative	6,884	6,780	13,805	13,932
Total operating expenses	39,494	40,935	79,193	82,965
Income (loss) from operations	(11,875)	(1,304)	996	26,552
Other income (expense):
Interest income (expense), net	1,950	2,245	4,026	4,130
Total other income (expense), net	1,950	2,245	4,026	4,130
Income (loss) before income taxes	(9,925)	941	5,022	30,682
Income tax (expense) benefit	3,920	3,204	2,416	(526)
Net income (loss)	$ (6,005)	$ 4,145	$ 7,438	$ 30,156
Net income (loss) per share:
Basic	$ (0.30)	$ 0.21	$ 0.37	$ 1.55
Diluted	$ (0.30)	$ 0.20	$ 0.36	$ 1.44
Weighted average shares outstanding:
Basic	19,922	19,549	19,836	19,487
Diluted	19,922	21,084	20,692	20,946

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (6,005)	$ 4,145	$ 7,438	$ 30,156
Other comprehensive income:
Net unrealized gains on marketable securities, net of tax of $119 and $78, $147 and $123	374	245	462	386
Total other comprehensive income, net of tax	374	245	462	386
Comprehensive income (loss)	$ (5,631)	$ 4,390	$ 7,900	$ 30,542

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net unrealized gains (losses) on marketable securities, tax	$ 119	$ 78	$ 147	$ 123

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Beginning Balance at Sep. 30, 2018	$ 393,679	$ 194	$ 276,526	$ (398)	$ 117,357
Beginning Balance, Shares at Sep. 30, 2018		19,395
Exercise of stock options	1,161		1,161
Exercise of stock options, Shares		40
Stock-based compensation expense	5,843		5,843
Total other comprehensive income, net of tax	141			141
Net income (loss)	26,011				26,011
Ending Balance at Dec. 31, 2018	426,835	$ 194	283,530	(257)	143,368
Ending Balance, Shares at Dec. 31, 2018		19,435
Beginning Balance at Sep. 30, 2018	393,679	$ 194	276,526	(398)	117,357
Beginning Balance, Shares at Sep. 30, 2018		19,395
Total other comprehensive income, net of tax	386
Net income (loss)	30,156
Ending Balance at Mar. 31, 2019	436,210	$ 197	288,512	(12)	147,513
Ending Balance, Shares at Mar. 31, 2019		19,669
Beginning Balance at Dec. 31, 2018	426,835	$ 194	283,530	(257)	143,368
Beginning Balance, Shares at Dec. 31, 2018		19,435
Exercise of stock options	4,466	$ 2	4,464
Exercise of stock options, Shares		157
Vesting of restricted stock units, net of withholding	(4,188)	$ 1	(4,189)
Vesting of restricted stock units, net of withholding, Shares		77
Stock-based compensation expense	4,707		4,707
Total other comprehensive income, net of tax	245			245
Net income (loss)	4,145				4,145
Ending Balance at Mar. 31, 2019	436,210	$ 197	288,512	(12)	147,513
Ending Balance, Shares at Mar. 31, 2019		19,669
Beginning Balance at Sep. 30, 2019	462,492	$ 197	298,409	146	163,740
Beginning Balance, Shares at Sep. 30, 2019		19,703
Exercise of stock options	2,306	$ 1	2,305
Exercise of stock options, Shares		76
Vesting of restricted stock units, net of withholding	(1,140)		(1,140)
Vesting of restricted stock units, net of withholding, Shares		31
Stock-based compensation expense	5,098		5,098
Total other comprehensive income, net of tax	88			88
Net income (loss)	13,443				13,443
Ending Balance at Dec. 31, 2019	482,287	$ 198	304,672	234	177,183
Ending Balance, Shares at Dec. 31, 2019		19,810
Beginning Balance at Sep. 30, 2019	$ 462,492	$ 197	298,409	146	163,740
Beginning Balance, Shares at Sep. 30, 2019		19,703
Exercise of stock options, Shares	237
Total other comprehensive income, net of tax	$ 462
Net income (loss)	7,438
Ending Balance at Mar. 31, 2020	485,991	$ 200	314,005	608	171,178
Ending Balance, Shares at Mar. 31, 2020		19,986
Beginning Balance at Dec. 31, 2019	482,287	$ 198	304,672	234	177,183
Beginning Balance, Shares at Dec. 31, 2019		19,810
Exercise of stock options	4,716	$ 2	4,714
Exercise of stock options, Shares		160
Vesting of restricted stock units, net of withholding	(358)		(358)
Vesting of restricted stock units, net of withholding, Shares		16
Stock-based compensation expense	4,977		4,977
Total other comprehensive income, net of tax	374			374
Net income (loss)	(6,005)				(6,005)
Ending Balance at Mar. 31, 2020	$ 485,991	$ 200	$ 314,005	$ 608	$ 171,178
Ending Balance, Shares at Mar. 31, 2020		19,986

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net income	$ 7,438	$ 30,156
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	10,076	10,550
Depreciation and amortization expense	1,819	1,482
Deferred income taxes	(1,224)	(800)
Premium paid on marketable securities	(2,398)	(1)
Accretion of discount on marketable securities	(379)	(2,213)
Other non-cash items		37
Change in operating assets and liabilities:
Accounts receivable	23,694	27,574
Prepaid expenses and other current assets	(4,536)	(9,598)
Operating lease, right-of-use assets	1,311
Accounts payable	(731)	2,886
Accrued expenses	(5,585)	1,259
Income taxes payable		(1,388)
Operating lease liabilities	(1,484)
Other long-term liabilities	(964)	396
Net cash provided by operating activities	27,037	60,340
Cash flows from investing activities
Purchase of marketable securities	(171,884)	(271,712)
Proceeds from maturities and sale of marketable securities	163,273	254,994
Purchase of property and equipment	(842)	(2,891)
Net cash used in investing activities	(9,453)	(19,609)
Cash flows from financing activities
Proceeds from exercise of stock options	7,022	5,627
Payments for settlement of share-based awards	(1,498)	(4,188)
Payments of capital lease obligations		(42)
Net cash provided by financing activities	5,524	1,397
Net increase (decrease) in cash, cash equivalents and restricted cash	23,108	42,128
Cash, cash equivalents and restricted cash at beginning of period	51,838	64,510
Cash, cash equivalents and restricted cash at end of period	74,946	106,638
Supplemental disclosure of cash flow information:
Cash paid for income taxes	50	9,955
Supplemental disclosure of non-cash investing information:
Purchases of fixed assets included in accounts payable and accrued expenses	109	$ 1,598
Operating lease liabilities arising from obtaining right-of-use assets	$ 1,997

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	6 Months Ended
	Mar. 31, 2020
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, a biotechnology company that uses its robust, chemistry-driven approach and drug discovery capabilities to create small molecule drugs for the treatment of viral infections and liver diseases. The Company discovered glecaprevir, the second protease inhibitor discovered and developed through its collaboration with AbbVie for the treatment of chronic hepatitis C virus, or HCV. Glecaprevir is co-formulated as part of AbbVie’s leading brand of direct-acting antiviral (DAA) combination treatment for HCV, which is marketed under the tradenames MAVYRET ® ® 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: 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 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 virus. National, state and local governments in affected regions have implemented and may continue to implement 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 full extent to which the COVID-19 pandemic will directly or indirectly impact 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 information that may emerge concerning COVID-19 and public health actions taken to contain it, as well as the cumulative economic impact of both of those factors. Unaudited Interim Financial Information The consolidated balance sheet at September 30, 2019 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, 2020 and for the six months ended March 31, 2020 and 2019 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 financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended September 30, 2019. 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, 2020 and results of operations for the three and six months ended March 31, 2020 and 2019 and cash flows for the six months ended March 31, 2020 and 2019, have been made. The results of operations for the three and six months ended March 31, 2020 are not necessarily indicative of the results of operations that may be expected for subsequent quarters or the year ending September 30, 2020. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Mar. 31, 2020
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, 2019. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). 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 Series 1 nonconvertible preferred stock and stock-based awards; the accrual of research and development expenses, and the accounting for income taxes, including uncertain tax positions and the valuation of net deferred tax assets. quarantines, border closures, increased border controls, travel restrictions, shelter-in-place orders and shutdowns, business closures, cancellations of public gatherings and other measures. Recently Adopted Accounting Pronouncements The Company adopted ASU No. 2016-02, Leases (Topic 842), as of October 1, 2019, using the modified retrospective method under ASU No. 2018-11, Leases (Topic 842): Targeted Improvements. The transition method allows entities to apply the transition requirements at the effective date rather than at the beginning of the earliest comparative period presented. The Company’s reporting for comparative periods is presented in accordance with ASC 840, Leases. Adoption of the new standard resulted in the recording of right of use (“ROU”) assets and lease liabilities of $7,151 and $8,622, respectively. The adoption of the standard did not have a material impact on the Company’s results of operations or cash flows. The Company elected to use the transition package of three practical expedients, which among other things, allowed the Company to carry forward the historical lease classification. The Company has elected, under Topic 842, the further practical expedient not to separate non-lease components from the lease components to which they relate and instead to combine them and account for them as a single lease component. The Company also elected the accounting policy election to keep leases with a term of twelve months or less off the balance sheet and to recognize payments for those leases on a straight-line basis over the lease term. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. At the inception of the arrangement, the Company determines if an arrangement is a lease based on an assessment of the terms and conditions of the contract. Operating lease ROU assets and lease liabilities are recognized at the commencement date, and thereafter, if modified, based on the present value of lease payments over the lease term. The lease term includes any renewal or early-termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. The underlying assets of the Company’s leases as of the adoption date consisted of office and laboratory space. In March 2017, the FASB issued ASU No. 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities (“ASU 2017-08”) which requires companies to amend the amortization period for premiums on debt securities with explicit call features to be the period through the earliest call date rather than through the contractual life of the debt instrument. This amendment aims to more closely align the recognition of interest income with the manner in which market participants price such instruments. The Company adopted the new standard on the effective date of October 1, 2019. T financial position and results of operations. Recently Issued Accounting Pronouncement s In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) (“ASU 2016-13”), which introduces a new methodology for accounting for credit losses on financial instruments, including available-for-sale debt securities. The guidance establishes a new “expected loss model” that requires entities to estimate current expected credit losses on financial instruments by using all practical and relevant information. Any expected credit losses are to be reflected as allowances rather than reductions in the amortized cost of available-for-sale debt securities. This amendment is effective for the Company in the fiscal year beginning October 1, 2020. The Company is currently evaluating the potential impact that ASU 2016-13 may have on its financial position and results of operations. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). This standard simplifies various aspects of the income tax accounting guidance in ASC 740, including requirements related to hybrid tax regimes, the tax basis step-up in goodwill obtained in a transaction that is not a business combination, separate financial statements of entities not subject to tax, the intra-period tax allocation exception to the incremental approach, ownership changes in investments, changes from a subsidiary to an equity method investment, interim-period accounting for enacted changes in tax law, and the year-to-date loss limitation in interim-period tax accounting. This amendment is effective for the Company in the fiscal year beginning October 1, 2021; however, early adoption is permitted. The Company is currently in the process of evaluating the impact that ASU 2019-12 may have on its consolidated financial statements. 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.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	6 Months Ended
	Mar. 31, 2020
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, 2020 and September 30, 2019, and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value: Fair Value Measurements at March 31, 2020 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 69,304 $ — $ — $ 69,304 Marketable securities: U.S. Treasury notes 168,191 — — 168,191 Commercial paper — 45,876 — 45,876 Corporate bonds — 146,949 — 146,949 $ 237,495 $ 192,825 $ — $ 430,320 Liabilities: Series 1 nonconvertible preferred stock $ — $ — $ 1,628 $ 1,628 $ — $ — $ 1,628 $ 1,628 Fair Value Measurements at September 30, 2019 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 44,569 $ — $ — $ 44,569 Marketable securities: U.S. Treasury notes 170,515 — — 170,515 Corporate bonds — 111,837 — 111,837 Commercial paper — 66,667 — 66,667 $ 215,084 $ 178,504 $ — $ 393,588 Liabilities: Series 1 nonconvertible preferred stock $ — $ — $ 1,628 $ 1,628 $ — $ — $ 1,628 $ 1,628 During the six months ended March 31, 2020 and 2019, there were no transfers between Level 1, Level 2 and Level 3. The outstanding shares of Series 1 nonconvertible preferred stock are measured at fair value. The fair value of these instruments was based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The Company utilized a probability-weighted valuation model which takes into consideration various outcomes that may require the Company to transfer assets upon exercise. Changes in the fair value of the Series 1 nonconvertible preferred stock are recognized in other income (expense), net 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 (Weighted Average) March 31, September 30, Unobservable Input 2020 2019 Probabilities of payout 0%-60% 0%-60% Discount rate 6.00% 6.00% The following table provides a rollforward of the aggregate fair values of the Company’s outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs: Series 1 Nonconvertible Preferred Stock Balance, September 30, 2019 $ 1,628 Change in fair value of nonconvertible preferred stock — Balance, March 31, 2020 $ 1,628

Marketable Securities

Marketable Securities	6 Months Ended
	Mar. 31, 2020
Investments Debt And Equity Securities [Abstract]
Marketable Securities	4. Marketable Securities As of March 31, 2020 and September 30, 2019, the fair value of available-for-sale marketable securities, by type of security, was as follows: March 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury notes $ 166,780 $ 1,411 $ — 168,191 Corporate bonds 147,608 17 (676 ) 146,949 Commercial Paper 45,876 — — 45,876 $ 360,264 $ 1,428 $ (676 ) $ 361,016 September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury notes $ 170,519 $ 60 $ (64 ) $ 170,515 Corporate bonds 111,690 170 (23 ) 111,837 Commercial Paper 66,667 — — 66,667 $ 348,876 $ 230 $ (87 ) $ 349,019 As of March 31, 2020 and September 30, 2019 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 three years and an aggregate fair value of $80,099 and $65,013, respectively.

Accrued Expenses and Other Long

Accrued Expenses and Other Long-Term Liabilities	6 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses and Other Long-Term Liabilities	5. Accrued Expenses and Other Long-Term Liabilities Accrued expenses and other current liabilities, as well as other long-term liabilities, consisted of the following as of March 31, 2020 and September 30, 2019: March 31, September 2020 2019 (in thousands) Accrued expenses: Accrued research and development expenses $ 2,880 $ 6,936 Accrued payroll and related expenses 1,969 3,894 Accrued clinical manufacturing 3,819 3,447 Accrued professional fees 499 759 Accrued other 640 884 $ 9,807 $ 15,920 Other long-term liabilities: Uncertain tax positions $ 764 $ 1,746 Accrued rent expense — 900 Capital lease obligation — 200 Asset retirement obligation 272 254 $ 1,036 $ 3,100

AbbVie Collaboration

AbbVie Collaboration	6 Months Ended
	Mar. 31, 2020
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 $975,000 through March 31, 2020. Since the Company satisfied all of its performance obligations under the AbbVie Agreement by the end of fiscal 2011, all milestone payments received since then have been recognized as revenue when the milestones were achieved by AbbVie. 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.

Series 1 Nonconvertible Preferr

Series 1 Nonconvertible Preferred Stock	6 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Series 1 Nonconvertible Preferred Stock	7. Series 1 Nonconvertible Preferred Stock As of March 31, 2020, 1,931 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 sheet.

Stock-Based Awards

Stock-Based Awards	6 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Awards	8. Stock-Based Awards The Company grants stock-based awards, including stock options and unit awards under its 2019 Equity Incentive Plan (the “2019 Plan”), which was approved by its stockholders on February 28, 2019. The Company also has outstanding unit awards, stock options and restricted stock unit 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, 2020: 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, 2019 2,967 $ 46.54 6.7 $ 57,336 Granted 684 61.80 Exercised (237 ) 29.68 Forfeited (100 ) 69.61 Outstanding as of March 31, 2020 3,314 $ 50.20 6.8 $ 32,699 Options vested and expected to vest as of March 31, 2020 3,314 $ 50.20 6.8 $ 32,699 Options exercisable as of March 31, 2020 1,978 $ 40.39 5.5 $ 30,213 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 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. 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, 2019 41 $ 73.02 41 $ 67.76 Granted 27 63.94 27 45.81 Vested (3 ) 77.93 (20 ) 84.70 Cancelled (19 ) 77.93 (2 ) 84.70 Unvested at March 31, 2020 46 65.23 46 $ 46.46 Restricted Stock Units During the three months ended December 31, 2016, the Company awarded restricted stock units to its employees, which vest 50% in three years and 50% in four years, provided the employee remains employed with the Company at the time of vesting. The fair value per share of these awards was determined based on the intrinsic value of the stock on the date of grant and is being recognized as stock-based compensation expense over the requisite service period. The following table summarizes the restricted stock unit activity for the year-to-date period ending March 31, 2020: Restricted Stock Units Weighted Average Grant Date Fair Value (in thousands, except per share data) Unvested at September 30, 2019 95 $ 30.00 Granted — — Vested (48 ) 30.00 Cancelled (2 ) 30.00 Unvested at March 31, 2020 45 $ 30.00 Stock-Based Compensation Expense During the three and six months ended March 31, 2020 and 2019, the Company recognized the following stock-based compensation expense: Three Months ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands) Research and development $ 2,688 $ 2,194 $ 5,180 $ 4,468 General and administrative 2,289 2,513 4,896 6,082 $ 4,977 $ 4,707 $ 10,076 $ 10,550 Three Months ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands) Stock options $ 4,441 $ 3,949 $ 8,777 $ 7,853 Performance stock units 16 72 259 1,278 rTSRUs 359 493 721 1,025 Restricted stock units 161 193 319 394 $ 4,977 $ 4,707 $ 10,076 $ 10,550 During the six months ended March 31, 2020 and 2019, 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 their respective performance periods. As of March 31, 2020, the Company had an aggregate of $47,904 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.6 years.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	6 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	9. Net Income (Loss) Per Share Basic and diluted net income (loss) per share attributable to common stockholders was calculated as follows for the three and six months ended March 31, 2020 and 2019: Three Months Ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands, except per share data) Basic net income (loss) per share: Numerator: Net income (loss) $ (6,005 ) $ 4,145 $ 7,438 $ 30,156 Denominator: Weighted average common shares outstanding —basic 19,922 19,549 19,836 19,487 Net income (loss) per share common share—basic $ (0.30 ) $ 0.21 $ 0.37 $ 1.55 Diluted net income (loss) per share: Numerator: Net income (loss) $ (6,005 ) $ 4,145 $ 7,438 $ 30,156 Denominator: Weighted average common shares outstanding —basic 19,922 19,549 19,836 19,487 Dilutive effect of common stock equivalents — 1,535 856 1,459 Weighted average common shares outstanding —diluted 19,922 21,084 20,692 20,946 Net income (loss) per share common share—diluted $ (0.30 ) $ 0.20 $ 0.36 $ 1.44 Anti-dilutive common stock equivalents excluded from above 3,714 784 2,457 694 The impact of certain common stock equivalents was excluded from the computation of diluted net loss per share for the periods in which the Company incurred a net loss since the impact of such common stock equivalents would have been anti-dilutive.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The Company’s provision for income taxes consists of federal and state taxes necessary to align the Company’s year-to-date tax provision with the annual effective rate that it expects to achieve for the full year. At each interim period, the Company updates its estimate of the annual effective tax rate and records cumulative adjustments as necessary. The authoritative guidance for accounting for income taxes allows use of the year-to-date effective tax rate (the “discrete method”) when a reliable estimate of the estimated annual effective tax rate cannot be made. During the six months ended March 31, 2020, the Company determined the use of the discrete method is more appropriate than the annual effective tax rate method due to the sensitivity of the Company’s tax rate to small changes in projected pre-tax earnings, which can result in significant variations in the customary relationship between income tax expense and pre-tax income. As such, the Company has discretely calculated the tax provision based on pre-tax results through the six months ended March 31, 2020. For the three months ended March 31, 2020 and 2019, the Company recorded an income tax benefit of $3,920 and $3,204, respectively, both of which were attributable to the Company’s domestic operations. The Company has no foreign operations and therefore, has not provided for any foreign taxes. For the six months ended March 31, 2020 and 2019, the Company recorded an income tax benefit of $2,416 and income tax (expense) of ($526), respectively. Although the Company reported pre-tax income for the six months ended March 31, 2020, the Company recorded an income tax benefit due to federal research and development tax credits, release of an uncertain tax position and stock award-related activity during the year. . 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. The Company’s tax years are still open under statute from 2016 to the present. Earlier years may be examined to the extent that tax credit or net operating loss carryforwards are used in future periods. During 2018, the Company received notice of examination by the Internal Revenue Service (“IRS”) for the year ending September 30, 2016. The Company received and agreed to a notice of proposed adjustment from the IRS, which was paid in September 2018, the amount of which was immaterial to the consolidated financial statements. The Company is in the process of finalizing the completion of the IRS audit. In addition, during October 2018 the Company received notice of examination by the Massachusetts Department of Revenue (“DOR”) for the years ending September 30, 2015 and September 30, 2016. The Company received a notice of proposed adjustment from the DOR, the amount of which was immaterial to the consolidated financial statements. The Company finalized the adjustment with the DOR during the three months ended March 31, 2020. The Company has not received notice of examination by any other jurisdictions for any other tax year open under statute. The Company had unrecognized tax benefits totaling $764 and $1,650 as of and , respectively. Unrecognized tax benefits represent tax positions for which reserves have been established. The Company’s policy is to record interest and penalties related to uncertain tax positions as part of its income tax provision. In conjunction with the finalization of the DOR audit, the Company released an uncertain tax benefit of $539 during the three months ended March 31, 2020 which was reflected in the income tax benefit reported during the period. In response to the COVID-19 pandemic, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was signed into law in March 2020. The CARES Act lifts certain deduction limitations originally imposed by the Tax Cuts and Jobs Act of 2017 (the “Tax Act”). Under the CARES Act, the Company is permitted to carry back net operating losses originating beginning in fiscal 2018 through fiscal 2020 for up to five years. Net operating loss carrybacks were previously prohibited under the Tax Act. The CARES Act also eliminates the 80% of taxable income limitations by allowing corporate entities to fully utilize net operating loss carryforwards to offset taxable income in fiscal years 2018, 2019 or 2020. In addition, the CARES Act makes qualified improvement property eligible for 15-year cost-recovery and 100% bonus depreciation. The enactment of the CARES Act did not result in any material adjustments to the Company’s consolidated financial statements for the three months ended March 31, 2020.

Leases

Leases	6 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	11. Leases The Company has two real estate leases for properties located in Watertown, Massachusetts. The first lease, for office and laboratory space at 500 Arsenal Street, was effective in fiscal 2011 and expires in September 2022 with an option to extend the lease term for an additional five years. The second lease, for office space located at 400 Talcott Avenue, was effective September 2018 and expires in August 2024 with two options to extend the lease term for an additional three years each. The options to extend the lease terms were not included in the right-of-use assets and lease liabilities as they were not reasonably certain of being exercised. he Company’s office and laboratory space leases require the Company to pay for certain operating expenses based on actual costs incurred and therefore as the amounts are variable in nature are expensed in the period incurred and included in variable lease costs. In October 2019, the Company entered into an agreement to lease units of equipment over eighteen-month lease periods commencing upon shipment of each unit. The lease agreement contains an option to terminate the lease early, however this early-termination option was not included in the right-of-use asset and lease liability as it was not reasonably certain of being exercised. and therefore, as these costs are variable in nature, they are expensed in the period incurred and included in variable lease costs. The components of lease expense for the Company’s real estate and equipment leases were as follows: Three Months Ended Six Months Ended March 31, 2020 March 31, 2020 (in thousands) Operating lease cost $ 950 $ 1,613 Short-term lease cost — — Variable lease cost 488 967 $ 1,438 $ 2,580 Other information: Three months ended Six months ended March 31, 2020 March 31, 2020 (in thousands) Cash paid for amounts included in the measurement of operating lease liabilities $ 1,048 $ 1,784 Operating lease liabilities arising from obtaining right-of-use assets $ 866 1,997 March 31, 2020 (in thousands) Weighted-average remaining lease term - operating leases (in years) 2.70 Weighted-average discount rate - operating leases 6.50 % Incremental borrowing rates were used to calculate the present value of the Company’s real estate and equipment leases. Future annual minimum lease payments under the Company’s real estate and equipment operating leases as of March 31, 2020 were as follows: Years ended September 30, (in thousands) 2020 $ 2,108 2021 3,927 2022 2,787 2023 608 2024 519 Total future minimum lease payments 9,949 Less: imputed interest (855 ) Total operating lease liabilities $ 9,094 Included in the balance sheet: March 31, 2020 (in thousands) Current operating lease liabilities $ 3,764 Operating lease liabilities, net of current portion 5,330 Total operating lease liabilities $ 9,094 As previously disclosed in the Company’s 2019 Annual Report on Form 10-K and under the previous lease accounting standard, ASC 840, Leases, the following table summarizes the future minimum lease payments due under the operating leases as of September 30, 2019: Years Ended September 30, Operating Leases Capital Leases (in thousands) 2020 $ 2,728 $ 93 2021 2,803 101 2022 2,684 99 2023 608 — 2024 519 — Total $ 9,342 $ 293 In connection with one of the real estate leases, the Company has a total outstanding letter of credit in the amount of $608

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. 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. The Company currently is not a party to any 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, 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. 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 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 March 31, 2020.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Use of Estimates	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 Series 1 nonconvertible preferred stock and stock-based awards; the accrual of research and development expenses, and the accounting for income taxes, including uncertain tax positions and the valuation of net deferred tax assets. quarantines, border closures, increased border controls, travel restrictions, shelter-in-place orders and shutdowns, business closures, cancellations of public gatherings and other measures.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements The Company adopted ASU No. 2016-02, Leases (Topic 842), as of October 1, 2019, using the modified retrospective method under ASU No. 2018-11, Leases (Topic 842): Targeted Improvements. The transition method allows entities to apply the transition requirements at the effective date rather than at the beginning of the earliest comparative period presented. The Company’s reporting for comparative periods is presented in accordance with ASC 840, Leases. Adoption of the new standard resulted in the recording of right of use (“ROU”) assets and lease liabilities of $7,151 and $8,622, respectively. The adoption of the standard did not have a material impact on the Company’s results of operations or cash flows. The Company elected to use the transition package of three practical expedients, which among other things, allowed the Company to carry forward the historical lease classification. The Company has elected, under Topic 842, the further practical expedient not to separate non-lease components from the lease components to which they relate and instead to combine them and account for them as a single lease component. The Company also elected the accounting policy election to keep leases with a term of twelve months or less off the balance sheet and to recognize payments for those leases on a straight-line basis over the lease term. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. At the inception of the arrangement, the Company determines if an arrangement is a lease based on an assessment of the terms and conditions of the contract. Operating lease ROU assets and lease liabilities are recognized at the commencement date, and thereafter, if modified, based on the present value of lease payments over the lease term. The lease term includes any renewal or early-termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. The underlying assets of the Company’s leases as of the adoption date consisted of office and laboratory space. In March 2017, the FASB issued ASU No. 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities (“ASU 2017-08”) which requires companies to amend the amortization period for premiums on debt securities with explicit call features to be the period through the earliest call date rather than through the contractual life of the debt instrument. This amendment aims to more closely align the recognition of interest income with the manner in which market participants price such instruments. The Company adopted the new standard on the effective date of October 1, 2019. T financial position and results of operations. Recently Issued Accounting Pronouncement s In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) (“ASU 2016-13”), which introduces a new methodology for accounting for credit losses on financial instruments, including available-for-sale debt securities. The guidance establishes a new “expected loss model” that requires entities to estimate current expected credit losses on financial instruments by using all practical and relevant information. Any expected credit losses are to be reflected as allowances rather than reductions in the amortized cost of available-for-sale debt securities. This amendment is effective for the Company in the fiscal year beginning October 1, 2020. The Company is currently evaluating the potential impact that ASU 2016-13 may have on its financial position and results of operations. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). This standard simplifies various aspects of the income tax accounting guidance in ASC 740, including requirements related to hybrid tax regimes, the tax basis step-up in goodwill obtained in a transaction that is not a business combination, separate financial statements of entities not subject to tax, the intra-period tax allocation exception to the incremental approach, ownership changes in investments, changes from a subsidiary to an equity method investment, interim-period accounting for enacted changes in tax law, and the year-to-date loss limitation in interim-period tax accounting. This amendment is effective for the Company in the fiscal year beginning October 1, 2021; however, early adoption is permitted. The Company is currently in the process of evaluating the impact that ASU 2019-12 may have on its consolidated financial statements. 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.

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	6 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities that were Subject to Fair Value Measurement on Recurring Basis	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, 2020 and September 30, 2019, and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value: Fair Value Measurements at March 31, 2020 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 69,304 $ — $ — $ 69,304 Marketable securities: U.S. Treasury notes 168,191 — — 168,191 Commercial paper — 45,876 — 45,876 Corporate bonds — 146,949 — 146,949 $ 237,495 $ 192,825 $ — $ 430,320 Liabilities: Series 1 nonconvertible preferred stock $ — $ — $ 1,628 $ 1,628 $ — $ — $ 1,628 $ 1,628 Fair Value Measurements at September 30, 2019 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 44,569 $ — $ — $ 44,569 Marketable securities: U.S. Treasury notes 170,515 — — 170,515 Corporate bonds — 111,837 — 111,837 Commercial paper — 66,667 — 66,667 $ 215,084 $ 178,504 $ — $ 393,588 Liabilities: Series 1 nonconvertible preferred stock $ — $ — $ 1,628 $ 1,628 $ — $ — $ 1,628 $ 1,628
Fair Value Measurements of the Company's Outstanding Series 1 Nonconvertible Preferred Stock	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 (Weighted Average) March 31, September 30, Unobservable Input 2020 2019 Probabilities of payout 0%-60% 0%-60% Discount rate 6.00% 6.00%
Rollforward of Aggregate Fair Values of Outstanding Series 1 Nonconvertible Preferred Stock	The following table provides a rollforward of the aggregate fair values of the Company’s outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs: Series 1 Nonconvertible Preferred Stock Balance, September 30, 2019 $ 1,628 Change in fair value of nonconvertible preferred stock — Balance, March 31, 2020 $ 1,628

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Mar. 31, 2020
Investments Debt And Equity Securities [Abstract]
Fair Value of Available-for-Sale Marketable Securities by Type of Security	As of March 31, 2020 and September 30, 2019, the fair value of available-for-sale marketable securities, by type of security, was as follows: March 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury notes $ 166,780 $ 1,411 $ — 168,191 Corporate bonds 147,608 17 (676 ) 146,949 Commercial Paper 45,876 — — 45,876 $ 360,264 $ 1,428 $ (676 ) $ 361,016 September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury notes $ 170,519 $ 60 $ (64 ) $ 170,515 Corporate bonds 111,690 170 (23 ) 111,837 Commercial Paper 66,667 — — 66,667 $ 348,876 $ 230 $ (87 ) $ 349,019

Accrued Expenses and Other Lo_2

Accrued Expenses and Other Long-Term Liabilities (Tables)	6 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities as well as Other Long-Term Liabilities	Accrued expenses and other current liabilities, as well as other long-term liabilities, consisted of the following as of March 31, 2020 and September 30, 2019: March 31, September 2020 2019 (in thousands) Accrued expenses: Accrued research and development expenses $ 2,880 $ 6,936 Accrued payroll and related expenses 1,969 3,894 Accrued clinical manufacturing 3,819 3,447 Accrued professional fees 499 759 Accrued other 640 884 $ 9,807 $ 15,920 Other long-term liabilities: Uncertain tax positions $ 764 $ 1,746 Accrued rent expense — 900 Capital lease obligation — 200 Asset retirement obligation 272 254 $ 1,036 $ 3,100

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	6 Months Ended
	Mar. 31, 2020
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, 2020: 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, 2019 2,967 $ 46.54 6.7 $ 57,336 Granted 684 61.80 Exercised (237 ) 29.68 Forfeited (100 ) 69.61 Outstanding as of March 31, 2020 3,314 $ 50.20 6.8 $ 32,699 Options vested and expected to vest as of March 31, 2020 3,314 $ 50.20 6.8 $ 32,699 Options exercisable as of March 31, 2020 1,978 $ 40.39 5.5 $ 30,213
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock unit activity for the year-to-date period ending March 31, 2020: Restricted Stock Units Weighted Average Grant Date Fair Value (in thousands, except per share data) Unvested at September 30, 2019 95 $ 30.00 Granted — — Vested (48 ) 30.00 Cancelled (2 ) 30.00 Unvested at March 31, 2020 45 $ 30.00
Stock-Based Compensation Expense	During the three and six months ended March 31, 2020 and 2019, the Company recognized the following stock-based compensation expense: Three Months ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands) Research and development $ 2,688 $ 2,194 $ 5,180 $ 4,468 General and administrative 2,289 2,513 4,896 6,082 $ 4,977 $ 4,707 $ 10,076 $ 10,550 Three Months ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands) Stock options $ 4,441 $ 3,949 $ 8,777 $ 7,853 Performance stock units 16 72 259 1,278 rTSRUs 359 493 721 1,025 Restricted stock units 161 193 319 394 $ 4,977 $ 4,707 $ 10,076 $ 10,550
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, 2020: 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, 2019 41 $ 73.02 41 $ 67.76 Granted 27 63.94 27 45.81 Vested (3 ) 77.93 (20 ) 84.70 Cancelled (19 ) 77.93 (2 ) 84.70 Unvested at March 31, 2020 46 65.23 46 $ 46.46

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	6 Months Ended
	Mar. 31, 2020
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 three and six months ended March 31, 2020 and 2019: Three Months Ended Six Months Ended March 31, March 31, 2020 2019 2020 2019 (in thousands, except per share data) Basic net income (loss) per share: Numerator: Net income (loss) $ (6,005 ) $ 4,145 $ 7,438 $ 30,156 Denominator: Weighted average common shares outstanding —basic 19,922 19,549 19,836 19,487 Net income (loss) per share common share—basic $ (0.30 ) $ 0.21 $ 0.37 $ 1.55 Diluted net income (loss) per share: Numerator: Net income (loss) $ (6,005 ) $ 4,145 $ 7,438 $ 30,156 Denominator: Weighted average common shares outstanding —basic 19,922 19,549 19,836 19,487 Dilutive effect of common stock equivalents — 1,535 856 1,459 Weighted average common shares outstanding —diluted 19,922 21,084 20,692 20,946 Net income (loss) per share common share—diluted $ (0.30 ) $ 0.20 $ 0.36 $ 1.44 Anti-dilutive common stock equivalents excluded from above 3,714 784 2,457 694 The impact of certain common stock equivalents was excluded from the computation of diluted net loss per share for the periods in which the Company incurred a net loss since the impact of such common stock equivalents would have been anti-dilutive.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Components of Lease Expense for Real Estate and Equipment Leases and Other Information Related to Leases	The components of lease expense for the Company’s real estate and equipment leases were as follows: Three Months Ended Six Months Ended March 31, 2020 March 31, 2020 (in thousands) Operating lease cost $ 950 $ 1,613 Short-term lease cost — — Variable lease cost 488 967 $ 1,438 $ 2,580 Other information: Three months ended Six months ended March 31, 2020 March 31, 2020 (in thousands) Cash paid for amounts included in the measurement of operating lease liabilities $ 1,048 $ 1,784 Operating lease liabilities arising from obtaining right-of-use assets $ 866 1,997 March 31, 2020 (in thousands) Weighted-average remaining lease term - operating leases (in years) 2.70 Weighted-average discount rate - operating leases 6.50 %
Schedule of Future Annual Minimum Lease Payments	Future annual minimum lease payments under the Company’s real estate and equipment operating leases as of March 31, 2020 were as follows: Years ended September 30, (in thousands) 2020 $ 2,108 2021 3,927 2022 2,787 2023 608 2024 519 Total future minimum lease payments 9,949 Less: imputed interest (855 ) Total operating lease liabilities $ 9,094
Schedule of Lease Included in Balance Sheet	Included in the balance sheet: March 31, 2020 (in thousands) Current operating lease liabilities $ 3,764 Operating lease liabilities, net of current portion 5,330 Total operating lease liabilities $ 9,094
Future Minimum Lease Payments	As previously disclosed in the Company’s 2019 Annual Report on Form 10-K and under the previous lease accounting standard, ASC 840, Leases, the following table summarizes the future minimum lease payments due under the operating leases as of September 30, 2019: Years Ended September 30, Operating Leases Capital Leases (in thousands) 2020 $ 2,728 $ 93 2021 2,803 101 2022 2,684 99 2023 608 — 2024 519 — Total $ 9,342 $ 293

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Detail)	6 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Entity incorporated, in year	1995

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2019	Mar. 31, 2020	Oct. 01, 2019
Accounting Policies [Abstract]
Lessee operating lease, option to extend	true
Lessee, operating lease, description	The Company has elected, under Topic 842, the further practical expedient not to separate non-lease components from the lease components to which they relate and instead to combine them and account for them as a single lease component. The Company also elected the accounting policy election to keep leases with a term of twelve months or less off the balance sheet and to recognize payments for those leases on a straight-line basis over the lease term.
Right-of-use asset		$ 7,837	$ 7,151
Lease liability		$ 9,094	$ 8,622

Fair Value of Financial Asset_3

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, 2020	Sep. 30, 2019
Assets:
Marketable securities	$ 361,016	$ 349,019
Assets, Fair Value Disclosure, Total	430,320	393,588
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,628	1,628
Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,628	1,628
Level 1 [Member]
Assets:
Assets, Fair Value Disclosure, Total	237,495	215,084
Level 2 [Member]
Assets:
Assets, Fair Value Disclosure, Total	192,825	178,504
Level 3 [Member]
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,628	1,628
Level 3 [Member] | Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,628	1,628
Money Market Funds [Member]
Assets:
Cash equivalents	69,304	44,569
Money Market Funds [Member] | Level 1 [Member]
Assets:
Cash equivalents	69,304	44,569
Corporate Bonds [Member]
Assets:
Marketable securities	146,949	111,837
Corporate Bonds [Member] | Level 2 [Member]
Assets:
Marketable securities	146,949	111,837
Commercial Paper [Member]
Assets:
Marketable securities	45,876	66,667
Commercial Paper [Member] | Level 2 [Member]
Assets:
Marketable securities	45,876	66,667
U.S. Treasury Notes [Member]
Assets:
Marketable securities	168,191	170,515
U.S. Treasury Notes [Member] | Level 1 [Member]
Assets:
Marketable securities	$ 168,191	$ 170,515

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0

Fair Value of Financial Asset_5

Fair Value of Financial Assets and Liabilities - Fair Value Measurements of the Company's Outstanding Series 1 Nonconvertible Preferred Stock (Detail) - Level 3 [Member]	Mar. 31, 2020	Sep. 30, 2019
Discount Rate [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Range (Weighted Average)	0.0600	0.0600
Minimum [Member] | Probabilities of Payout [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Range (Weighted Average)	0	0
Maximum [Member] | Probabilities of Payout [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Range (Weighted Average)	60	60

Fair Value of Financial Asset_6

Fair Value of Financial Assets and Liabilities - Rollforward of Aggregate Fair Values of Outstanding Series 1 Nonconvertible Preferred Stock (Detail) - Series 1 Nonconvertible Preferred Stock [Member] $ in Thousands	Mar. 31, 2020USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 1,628
Ending Balance	$ 1,628

Marketable Securities - Fair Va

Marketable Securities - Fair Value of Available-for-Sale Marketable Securities by Type of Security (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 360,264	$ 348,876
Gross Unrealized Gains	1,428	230
Gross Unrealized Losses	(676)	(87)
Fair Value	361,016	349,019
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,876	66,667
Fair Value	45,876	66,667
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	147,608	111,690
Gross Unrealized Gains	17	170
Gross Unrealized Losses	(676)	(23)
Fair Value	146,949	111,837
U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	166,780	170,519
Gross Unrealized Gains	1,411	60
Gross Unrealized Losses		(64)
Fair Value	$ 168,191	$ 170,515

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Sep. 30, 2019
Schedule of Available-for-sale Securities [Line Items]
Long-term marketable securities	$ 80,099	$ 65,013
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	3 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

Accrued Expenses and Other Lo_3

Accrued Expenses and Other Long-Term Liabilities - Accrued Expenses and Other Current Liabilities as well as Other Long-Term Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Accrued expenses:
Accrued research and development expenses	$ 2,880	$ 6,936
Accrued payroll and related expenses	1,969	3,894
Accrued clinical manufacturing	3,819	3,447
Accrued professional fees	499	759
Accrued other	640	884
Accrued expenses	9,807	15,920
Other long-term liabilities:
Uncertain tax positions	764	1,746
Accrued rent expense		900
Capital lease obligation		200
Asset retirement obligation	272	254
Other long-term liabilities	$ 1,036	$ 3,100

AbbVie Collaboration - Addition

AbbVie Collaboration - Additional Information (Detail) - AbbVie [Member] $ in Thousands	6 Months Ended
	Mar. 31, 2020USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cash consideration received under collaboration from sale of preferred stock, research funding payments, milestone payments and royalties	$ 975,000
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

Series 1 Nonconvertible Prefe_2

Series 1 Nonconvertible Preferred Stock - Additional Information (Detail) - Series 1 Nonconvertible Preferred Stock [Member] shares in Thousands	Mar. 31, 2020shares
Class Of Stock [Line Items]
Preferred stock, shares issued	1,931
Preferred stock, shares outstanding	1,931

Stock-Based Awards - Summary of

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, 2020USD ($)$ / sharesshares	Sep. 30, 2019USD ($)$ / sharesshares
Options
Outstanding as of beginning of period | shares	2,967
Granted | shares	684
Exercised | shares	(237)
Forfeited | shares	(100)
Outstanding as of end of period | shares	3,314	2,967
Options vested and expected to vest as of end of period | shares	3,314
Options exercisable as of end of period | shares	1,978
Weighted Average Exercise Price
Outstanding | $ / shares	$ 46.54
Granted | $ / shares	61.80
Exercised | $ / shares	29.68
Forfeited | $ / shares	69.61
Outstanding | $ / shares	50.20	$ 46.54
Options vested and expected to vest as of end of period | $ / shares	50.20
Options exercisable as of end of period | $ / shares	$ 40.39
Weighted Average Remaining Contractual Term
Outstanding as of end of period	6 years 9 months 18 days	6 years 8 months 12 days
Options vested and expected to vest as of end period	6 years 9 months 18 days
Options exercisable as of end of period	5 years 6 months
Aggregate Intrinsic Value
Aggregate Intrinsic Value | $	$ 32,699	$ 57,336
Options vested and expected to vest as of March 31, 2020 | $	32,699
Options exercisable as of end of period | $	$ 30,213

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Dec. 31, 2016	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate of unrecognized stock-based compensation cost		$ 47,904
Weighted average recognition period		2 years 7 months 6 days
Restricted Stock Units [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Vesting period	3 years
Restricted Stock Units [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Vesting period	4 years
Executive Officers [Member] | Relative Total Stockholder Return Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares range percentage		0.00%
Executive Officers [Member] | Relative Total Stockholder Return Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares range percentage		150.00%

Stock-Based Awards - Summary _2

Stock-Based Awards - Summary of PSUs and rTSRUs Activity (Detail) shares in Thousands	6 Months Ended
	Mar. 31, 2020$ / sharesshares
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	41
Granted | shares	27
Vested | shares	(3)
Cancelled | shares	(19)
Unvested, ending balance | shares	46
Weighted Average Grant Date Fair Value, Unvested beginning balance | $ / shares	$ 73.02
Weighted Average Grant Date Fair Value, Granted | $ / shares	63.94
Weighted Average Grant Date Fair Value, Vested | $ / shares	77.93
Weighted Average Grant Date Fair Value, Cancelled | $ / shares	77.93
Weighted Average Grant Date Fair Value, Unvested ending balance | $ / shares	$ 65.23
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	41
Granted | shares	27
Vested | shares	(20)
Cancelled | shares	(2)
Unvested, ending balance | shares	46
Weighted Average Grant Date Fair Value, Unvested beginning balance | $ / shares	$ 67.76
Weighted Average Grant Date Fair Value, Granted | $ / shares	45.81
Weighted Average Grant Date Fair Value, Vested | $ / shares	84.70
Weighted Average Grant Date Fair Value, Cancelled | $ / shares	84.70
Weighted Average Grant Date Fair Value, Unvested ending balance | $ / shares	$ 46.46

Stock-Based Awards - Summary _3

Stock-Based Awards - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member] shares in Thousands	6 Months Ended
	Mar. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	95
Granted | shares	0
Vested | shares	(48)
Cancelled | shares	(2)
Unvested, ending balance | shares	45
Weighted Average Grant Date Fair Value, Unvested beginning balance | $ / shares	$ 30
Weighted Average Grant Date Fair Value, Granted | $ / shares	0
Weighted Average Grant Date Fair Value, Vested | $ / shares	30
Weighted Average Grant Date Fair Value, Cancelled | $ / shares	30
Weighted Average Grant Date Fair Value, Unvested ending balance | $ / shares	$ 30

Stock-Based Awards - Stock-Base

Stock-Based Awards - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 4,977	$ 4,707	$ 10,076	$ 10,550
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	4,441	3,949	8,777	7,853
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	16	72	259	1,278
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	359	493	721	1,025
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	161	193	319	394
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	2,688	2,194	5,180	4,468
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,289	$ 2,513	$ 4,896	$ 6,082

Net Income (Loss) Per Share - B

Net Income (Loss) Per Share - Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2020	Mar. 31, 2019
Basic net income (loss) per share:
Net income (loss)	$ (6,005)	$ 13,443	$ 4,145	$ 26,011	$ 7,438	$ 30,156
Weighted average common shares outstanding —basic	19,922		19,549		19,836	19,487
Net income (loss) per share common share—basic	$ (0.30)		$ 0.21		$ 0.37	$ 1.55
Diluted net income (loss) per share:
Net income (loss)	$ (6,005)	$ 13,443	$ 4,145	$ 26,011	$ 7,438	$ 30,156
Basic	19,922		19,549		19,836	19,487
Dilutive effect of common stock equivalents			1,535		856	1,459
Weighted average common shares outstanding —diluted	19,922		21,084		20,692	20,946
Net income (loss) per share common share—diluted	$ (0.30)		$ 0.20		$ 0.36	$ 1.44
Anti-dilutive common stock equivalents excluded from above	3,714		784		2,457	694

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax (expense) benefit	$ 3,920	$ 3,204	$ 2,416	$ (526)
Federal income tax (expense) benefit				$ (526)
Unrecognized tax benefits	764		$ 764		$ 1,650
Uncertain tax benefits	$ 539
Description of effects of COVID-19			In response to the COVID-19 pandemic, the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”) was signed into law in March 2020. The CARES Act lifts certain deduction limitations originally imposed by the Tax Cuts and Jobs Act of 2017 (the “Tax Act”). Under the CARES Act, the Company is permitted to carry back net operating losses originating beginning in fiscal 2018 through fiscal 2020 for up to five years. Net operating loss carrybacks were previously prohibited under the Tax Act. The CARES Act also eliminates the 80% of taxable income limitations by allowing corporate entities to fully utilize net operating loss carryforwards to offset taxable income in fiscal years 2018, 2019 or 2020. In addition, the CARES Act makes qualified improvement property eligible for 15-year cost-recovery and 100% bonus depreciation. The enactment of the CARES Act did not result in any material adjustments to the Company’s consolidated financial statements for the three months ended March 31, 2020

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	6 Months Ended
	Mar. 31, 2020USD ($)Lease	Oct. 31, 2019	Sep. 30, 2019USD ($)
Lessee Lease Description [Line Items]
Number of leases | Lease	2
Lease periods commencing upon shipment		18 months
Outstanding letter of credit	$ 608		$ 608
Restricted cash	$ 608		$ 608
First Lease [Member] | 500 Arsenal Street, Watertown, Massachusetts [Member]
Lessee Lease Description [Line Items]
Office lease expiration period	2022-09
Lease option to extend	an option to extend the lease term for an additional five years.
Second Lease [Member] | 400 Talcott Avenue, Watertown, Massachusetts [Member]
Lessee Lease Description [Line Items]
Office lease expiration period	2024-08
Period of lease agreement	2018-09
Lease option to extend	two options to extend the lease term for an additional three years each.

Leases - Components of Lease Ex

Leases - Components of Lease Expense for Real Estate and Equipment Leases and Other Information Related to Leases (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2020USD ($)	Mar. 31, 2020USD ($)
Leases [Abstract]
Operating lease cost	$ 950	$ 1,613
Variable lease cost	488	967
Lease, Cost	1,438	2,580
Cash paid for amounts included in the measurement of operating lease liabilities	1,048	1,784
Operating lease liabilities arising from obtaining right-of-use assets	$ 866	$ 1,997
Weighted-average remaining lease term - operating leases (in years)	2 years 8 months 12 days	2 years 8 months 12 days
Weighted-average discount rate - operating leases	6.50%	6.50%

Leases - Schedule of Future Ann

Leases - Schedule of Future Annual Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Oct. 01, 2019
Leases [Abstract]
2020	$ 2,108
2021	3,927
2022	2,787
2023	608
2024	519
Total future minimum lease payments	9,949
Less: imputed interest	(855)
Lease liability	$ 9,094	$ 8,622

Leases - Schedule of Lease Incl

Leases - Schedule of Lease Included in Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Oct. 01, 2019
Leases [Abstract]
Operating lease liabilities	$ 3,764
Operating lease liabilities, net of current portion	5,330
Total operating lease liabilities	$ 9,094	$ 8,622

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Leases [Abstract]
2020	$ 2,728
2021	2,803
2022	2,684
2023	608
2024	519
Total	9,342
2020	93
2021	101
2022	99
Total	$ 293