Enanta Pharmaceuticals (ENTA) 10-K 29 Nov 18 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2018	Nov. 01, 2018	Mar. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	ENTA
Entity Registrant Name	ENANTA PHARMACEUTICALS INC
Entity Central Index Key	1,177,648
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		19,423,949
Entity Public Float			$ 1,280,474,378

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 63,902	$ 65,675
Short-term marketable securities	244,828	157,994
Accounts receivable	67,205	10,614
Prepaid expenses and other current assets	4,454	3,536
Total current assets	380,389	237,819
Long-term marketable securities	16,389	70,038
Property and equipment, net	8,374	8,049
Deferred tax assets	8,375	10,123
Restricted cash	608	608
Other long-term assets	92
Total assets	414,227	326,637
Current liabilities:
Accounts payable	4,745	3,714
Accrued expenses and other current liabilities	9,892	7,970
Income taxes payable	1,388	9,298
Total current liabilities	16,025	20,982
Warrant liability		807
Series 1 nonconvertible preferred stock	1,628	762
Other long-term liabilities	2,895	2,410
Total liabilities	20,548	24,961
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock; $0.01 par value per share, 100,000 shares authorized; 19,395 and 19,120 shares issued and outstanding at September 30, 2018 and September 30, 2017, respectively	194	191
Additional paid-in capital	276,526	256,241
Accumulated other comprehensive loss	(398)	(112)
Retained earnings	117,357	45,356
Total stockholders' equity	393,679	301,676
Total liabilities and stockholders' equity	$ 414,227	$ 326,637

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Sep. 30, 2017
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	19,395,000	19,120,000
Common stock, shares outstanding	19,395,000	19,120,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Revenue
Total revenue	$ 206,625	$ 102,814	$ 88,268
Operating expenses:
Research and development	94,856	57,451	40,461
General and administrative	23,441	20,749	16,966
Total operating expenses	118,297	78,200	57,427
Income from operations	88,328	24,614	30,841
Other income (expense):
Interest income (expense), net	4,852	2,492	1,690
Change in fair value of warrant liability and Series 1 nonconvertible preferred stock	(59)	(159)	29
Total other income (expense), net	4,793	2,333	1,719
Income before income taxes	93,121	26,947	32,560
Income tax expense	(21,165)	(9,237)	(10,894)
Net income	$ 71,956	$ 17,710	$ 21,666
Net income per share:
Basic	$ 3.74	$ 0.93	$ 1.14
Diluted	$ 3.48	$ 0.91	$ 1.13
Weighted average shares outstanding:
Basic	19,255	19,066	18,929
Diluted	20,650	19,407	19,224
Royalties [Member]
Revenue
Total revenue	$ 191,625	$ 37,814	$ 57,692
Milestone [Member]
Revenue
Total revenue	$ 15,000	$ 65,000	30,000
Other [Member]
Revenue
Total revenue			$ 576

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 71,956	$ 17,710	$ 21,666
Other comprehensive loss:
Net unrealized losses on marketable securities, net of tax benefit of ($109), ($78), and ($9)	(286)	(131)	(14)
Total other comprehensive loss	(286)	(131)	(14)
Comprehensive income	$ 71,670	$ 17,579	$ 21,652

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net unrealized losses on marketable securities, tax benefit	$ (109)	$ (78)	$ (9)

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, 2015	$ 236,157	$ 187	$ 229,957	$ 33	$ 5,980
Beginning Balance, Shares at Sep. 30, 2015		18,717
Exercise of stock options	1,026	$ 3	1,023
Exercise of stock options, Shares		319
Stock-based compensation expense	9,354		9,354
Income tax benefit from stock option exercises	1,747		1,747
Other comprehensive loss	(14)			(14)
Net income	21,666				21,666
Ending Balance at Sep. 30, 2016	269,936	$ 190	242,081	19	27,646
Ending Balance, Shares at Sep. 30, 2016		19,036
Exercise of stock options	1,079	$ 1	1,078
Exercise of stock options, Shares		72
Vesting of restricted stock units, net of withholding	(202)		(202)
Vesting of restricted stock units, net of withholding, Shares		12
Stock-based compensation expense	13,071		13,071
Income tax benefit from stock option exercises	213		213
Other comprehensive loss	(131)			(131)
Net income	17,710				17,710
Ending Balance at Sep. 30, 2017	$ 301,676	$ 191	256,241	(112)	45,356
Ending Balance, Shares at Sep. 30, 2017		19,120
Exercise of stock options, Shares	229
Exercise of stock options and warrants	$ 6,244	$ 2	6,242
Exercise of stock options and warrants, Shares		230
Vesting of restricted stock units, net of withholding	(1,756)	$ 1	(1,757)
Vesting of restricted stock units, net of withholding, Shares		45
Stock-based compensation expense	15,845		15,845
Other comprehensive loss	(286)			(286)
Net income	71,956				71,956
Ending Balance at Sep. 30, 2018	$ 393,679	$ 194	276,526	$ (398)	117,357
Ending Balance, Shares at Sep. 30, 2018		19,395
Cumulative effect adjustment for adoption of new accounting guidance (Note 2)			$ (45)		$ 45

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net income	$ 71,956	$ 17,710	$ 21,666
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	15,845	13,071	9,354
Depreciation and amortization expense	2,518	2,137	1,661
Deferred income taxes	1,858	(1,654)	(2,294)
Income tax benefit from stock awards		(213)	(1,747)
Premium paid on marketable securities	(319)	(1,229)	(518)
Amortization of (accretion of) premium (discount) on marketable securities	(835)	702	1,511
Change in fair value of warrant liability and Series 1 nonconvertible preferred stock	59	159	(29)
Other non-cash items	(75)		34
Change in operating assets and liabilities:
Accounts receivable	(56,591)	2,227	2,448
Unbilled receivables			433
Prepaid expenses and other current assets	(918)	5,678	(964)
Accounts payable	1,317	633	1,451
Accrued expenses	1,843	3,443	1,858
Income taxes payable	(7,910)	9,511	548
Other long-term liabilities	564	478	397
Other long-term assets	(92)
Net cash provided by operating activities	29,220	52,653	35,809
Cash flows from investing activities
Purchase of marketable securities	(293,103)	(251,371)	(192,429)
Proceeds from maturities and sale of marketable securities	260,682	249,305	153,504
Purchase of property and equipment	(2,981)	(2,506)	(4,738)
Net cash used in investing activities	(35,402)	(4,572)	(43,663)
Cash flows from financing activities
Proceeds from exercise of stock options and warrants	6,244	1,079	1,026
Income tax benefit from exercise of stock options		213	1,747
Payments for settlement of share-based awards	(1,756)	(202)
Payments of capital lease obligations	(79)	(73)	(68)
Net cash provided by financing activities	4,409	1,017	2,705
Net increase (decrease) in cash and cash equivalents	(1,773)	49,098	(5,149)
Cash and cash equivalents at beginning of period	65,675	16,577	21,726
Cash and cash equivalents at end of period	63,902	65,675	16,577
Supplemental disclosure of cash flow information:
Cash paid for income taxes	26,088	1,588	12,616
Non-cash items:
Purchases of fixed assets included in accounts payable and accrued expenses	$ 111	$ 318	$ 637

Nature of the Business

Nature of the Business	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business 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 create small molecule drugs primarily 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, which is marketed as part of AbbVie’s direct-acting antiviral (DAA) regimen under the tradenames MAVYRET™ (U.S.) or MAVIRET™ (ex-U.S.) (glecaprevir/pibrentasvir) for the treatment of chronic hepatitis C virus, or HCV. The other protease inhibitor under its HCV collaboration, which is part of AbbVie’s initial DAA regimens for the treatment of chronic HCV, is currently marketed outside the U.S. under the tradename VIEKIRAX ® Royalties from the Company’s AbbVie collaboration and its existing financial resources provide funding to support its wholly-owned research and development programs , which are currently 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiary, Enanta Pharmaceuticals Security Corporation, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Use of Estimates The preparation of 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 warrants, 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. Cash Equivalents and Marketable Securities The Company considers all short-term, highly liquid investments with original maturities of ninety days or less at acquisition date to be cash equivalents. Marketable securities with original maturities of greater than ninety days and remaining maturities of less than one year from the balance sheet date are classified as short-term marketable securities. Marketable securities with remaining maturities of greater than one year from the balance sheet date are classified as long-term marketable securities. The Company classifies all of its marketable securities as available-for-sale. The Company continually evaluates the credit ratings of its investment portfolio and underlying securities. The Company invests in accordance with its investment policy and invests at the date of purchase in securities with a rating of A3 or higher and A- or higher according to Moody’s and S&P, respectively. The Company reports available-for-sale investments at fair value as of each balance sheet date and records any unrealized gains or losses as a component of stockholders’ equity. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense), net within the consolidated statements of operations. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate the extent to which the decline is “other than temporary” and reduces the investment to fair value through a charge to the consolidated statements of operations. There were no such adjustments necessary during the years ended September 30, 2018, 2017, and 2016. Restricted Cash As of September 30, 2018 and 2017 the Company had an outstanding letter of credit collateralized by a money market account of $608 to the benefit of the landlord of the Company’s current building lease. This amount was classified as long-term restricted cash as of September 30, 2018 and 2017. Concentration of Credit Risk and of Significant Customers and Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities and accounts receivable. The Company has all cash and investment balances at one accredited financial institution, including cash in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company has historically generated all of its revenue from its collaborative research and license agreements as well as a U.S. government contract (see Note 7). As of September 30, 2018 and 2017, accounts receivable consisted of amounts due from the Company’s principal collaborator (see Note 7). The Company is completely dependent on third-party manufacturers for product supply for preclinical and clinical research activities in its non-partnered programs. The Company relies and expects to continue to rely exclusively on several manufacturers to supply the Company with its requirements for the active pharmaceutical ingredients related to these programs. These research programs would be adversely affected by a significant interruption in the supply of its active pharmaceutical ingredients. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. A fair value hierarchy is based on three levels of inputs which are used to measure fair value, of which the first two levels are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices) such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s instruments that are carried at fair value are cash equivalents, marketable securities and the warrant and Series 1 nonconvertible preferred stock liabilities. The carrying values of accounts receivable, accounts payable and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. Property and Equipment Property and equipment are stated at cost less accumulated depreciation or amortization. Depreciation and amortization expense is recognized using the straight-line method over the following estimated useful lives: Laboratory and office equipment 5 years Leasehold improvements Shorter of life of lease or estimated useful life Purchased software 3 years Computer equipment 3 years Furniture 7 years Expenditures for repairs and maintenance of assets are charged to expense as incurred. Costs of major additions and betterments are capitalized and depreciated on a straight-line basis over their useful lives. Upon retirement or sale, the cost and related accumulated depreciation or amortization of assets disposed are removed from the accounts and any resulting gain or loss is included in income from operations in the consolidated statements of operations. Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Revenue Recognition The Company’s revenue has been generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables, which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectibility of the resulting receivable is reasonably assured, and the Company has fulfilled its performance obligations under the contract. The consideration received under multiple-element arrangements that is fixed or determinable is allocated among the separate units of accounting based on the relative selling prices of the separate units of accounting. The Company determines the selling price of a unit of accounting within each arrangement following the hierarchy of evidence prescribed by ASC 605-25 In determining the separate units of accounting, the Company evaluates whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers whether or not (i) the collaborator can use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license is dependent on the undelivered items, and (iii) the collaborator or other vendors can provide the undelivered items. For all periods presented, whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model or a straight-line model over the period of performance, which is typically the research and development term. Full-time equivalents (“FTEs”) are typically used as the measure of performance. At each reporting period, the Company reassesses its cumulative measure of performance and makes appropriate adjustments, if necessary. The Company recognizes revenue using the proportional performance model whenever the Company can make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement. Revenue recognized under the proportional performance model at each reporting period is determined by multiplying the total expected payments under the contract (excluding royalties and payments contingent upon achievement of milestones) by the ratio of the level of effort incurred to date to the estimated total level of effort required to complete the performance obligations under the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model as of each reporting period. Alternatively, if the Company cannot make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement, then revenue under the arrangement is recognized on a straight-line basis over the period expected to complete the Company’s performance obligations. If and when a contingent milestone payment is earned, the additional consideration to be received is allocated to the separate units of accounting in the arrangement based on their relative selling prices at the inception of the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined on a straight-line basis as of the period end date. If the Company cannot reasonably estimate when its performance obligation period ends, then revenue is deferred until the Company can reasonably estimate when the performance obligation period ends. Royalty revenue is recognized based on contractual terms when reported sales are reliably measurable and collectibility is reasonably assured, provided that there are no performance obligations remaining. During the year ended September 30, 2016, the Company also generated revenue from a government contract, under which the Company was reimbursed for certain allowable costs for the funded project. Revenue from the government contract was recognized when the related service was performed. The related costs incurred by the Company under the government contract were included in research and development expenses in the consolidated statements of operations. Amounts received prior to satisfying all revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the next twelve months of the consolidated balance sheet date are classified as long-term deferred revenue. In the event that a collaborative research and license agreement is terminated and the Company then has no further performance obligations, the Company recognizes as revenue any amounts that had not previously been recorded as revenue but were classified as deferred revenue at the date of such termination. Research and Development Costs Research and development costs are expensed as incurred. Included in research and development costs are wages, stock-based compensation and benefits of employees, third-party license fees and other operational costs related to the Company’s research and development activities, including facility-related expenses and external costs of outside contractors engaged to conduct both preclinical and clinical studies and manufacture quantities of product for preclinical and clinical studies. The Company also includes in research and development expense the costs to complete the Company’s obligations under research collaborations. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development in the period in which they are incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed. Research and Manufacturing Contract Accruals The Company has entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. The Company records accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research and development and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company's estimates. The Company's historical accrual estimates have not been materially different from the actual costs. Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are recorded as general and administrative expenses as incurred. Stock-Based Compensation The Company measures all stock options and other stock-based awards granted to employees at fair value on the date of grant. The Company uses the Black-Scholes option-pricing model in the valuation of its stock options. The fair value of performance-based awards and restricted stock units is based on intrinsic value of the stock on the date of grant. The Company uses the Monte-Carlo model in order to calculate the fair value of the market-based awards. The fair value of options is recognized as stock-based compensation expense over the requisite service period, which is generally the vesting period of the respective award. Commencing with the adoption of ASU No. 2016-09 on October 1, 2017, t Income Taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. Uncertain tax positions represent tax positions for which reserves have been established. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely than not to be sustained, the tax position is then assessed to determine the amount of benefit to be recognized in the financial statements. The amount that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. Income tax expense includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Net Income per Share Basic net income per common share is computed by dividing the net income by the weighted average number of shares of common stock outstanding for the period. Diluted net income per common share is computed by dividing net income 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. Market-based awards are included in diluted net income per common share to the extent they would have vested if the period end date was the market criteria measurement date. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is a biotechnology company focused on discovering and developing small molecule drugs for the treatment of viral infections and liver diseases. Revenue is generated exclusively from transactions occurring with partners located in the United States and all assets are held in the United States. Comprehensive Income Comprehensive income includes net income as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income is unrealized gains and losses on available-for-sale marketable securities. Going Concern In August 2014, the Financial Accounting Standards Board (the “ Presentation of Financial Statements - Going Concern (Subtopic 205-40) . Based on a detailed cash forecast incorporating current research and development activities and related spending plans, the Company believes that current cash, cash equivalents and marketable securities on hand at September 30, 2018 should be sufficient to fund operations for the foreseeable future, including at least the next twelve months beyond the date of issuance of these financial statements. The amount of capital available will depend on the Company’s management of its existing cash, cash equivalents and marketable securities, as well as the level of future royalties the Company earns under its agreement with AbbVie. If the Company should require financing beyond these resources to fund its research and development efforts, it may not be able to obtain financing on acceptable terms, or at all. Recently Issued Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), which intends to simplify several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, a choice to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. This amendment was effective for the Company in the fiscal year beginning October 1, 2017. As a result of the adoption, the Company changed its forfeiture rate policy to recognize forfeitures as they occur. Upon adoption, the cumulative impact of this accounting policy change on retained earnings, additional paid-in capital and deferred tax assets in the consolidated balance sheet was not material. In addition, the consolidated statements of cash flows now presents excess tax benefits as part of cash flows from operating activities. The Company elected to adopt this change on a prospective basis and, therefore, excess tax benefits from prior periods in the consolidated statements of cash flow were not restated. The adoption of the standard is also expected to create variability in the consolidated statements of operations in years in which the Company is expected to have taxable income, as the tax consequences of settled share-based payments will be recognized in income tax expense when share-based payment awards are settled. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”) which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. The FASB has continued to issue accounting standards updates to clarify and provide implementation guidance related to Revenue from Contracts with Customers, including ASU 2016-08 , Revenue from Contract with Customers: Principal versus Agent Considerations , ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing , and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. These amendments address a number of areas, including an entity’s identification of its performance obligations in a contract, collectibility, non-cash consideration, presentation of sales tax and an entity’s evaluation of the nature of its promise to grant a license of intellectual property and whether or not that revenue is recognized over time or at a point in time. The new guidance must be adopted using either a modified retrospective approach or a full retrospective approach for all periods presented. Under the modified retrospective method, the cumulative effect of applying the new standard would be recognized at the adoption date in retained earnings on the consolidated balance sheet. Under the full retrospective approach, the new standard would be applied to each prior reporting period presented. These new standards will be effective for the Company beginning October 1, 2018. The Company will adopt the standard under the modified retrospective method, the impact of which is not expected to have a material impact on the Company’s consolidated financial statements as the AbbVie Agreement is the only revenue-generating arrangement outstanding and all performance obligations under the agreement have been completed by the end of fiscal 2011. The adoption of ASU 2014-09 did not have an impact on the Company’s accounting for contingent milestone or royalty payments. All contingent milestone payments earned since fiscal 2011 have been recognized as revenue when the associated milestone was achieved by AbbVie . The Company is currently earning annually tiered per-product royalties on the portion of AbbVie’s net sales of its HCV regimens allocable to the protease inhibitor product in the regimen. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”) that changes the presentation of restricted cash and cash equivalents on the statement of cash flows. Restricted cash and restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. Upon adoption, the Company will adjust the presentation of the statement of cash flows to include restricted cash related to an outstanding letter of credit collateralized by a money market fund of $608 so that it is included in the balances of cash and cash equivalents. In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718) (“ASU 2017-09”) which This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which will replace the existing guidance in ASC 840, “Leases.” The updated standard aims to increase transparency and comparability among organizations by requiring lessees to recognize leased assets and leased liabilities on the consolidated balance sheets and requiring disclosure of key information about leasing arrangements. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2016-02 may have on its financial position and results of operations. 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 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. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2017-08 may have on its financial position and results of operations. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (“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. 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	12 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities The following tables present information about the Company’s financial assets and liabilities that were subject to fair value measurement on a recurring basis as of September 30, 2018 and 2017 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value: Fair Value Measurements at September 30, 2018 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 51,025 $ — $ — $ 51,025 Commercial paper — 6,987 — 6,987 Corporate bonds — 3,998 — 3,998 Marketable securities: U.S. Treasury notes 42,703 — — 42,703 Commercial paper — 113,885 — 113,885 Corporate bonds — 104,629 — 104,629 $ 93,728 $ 229,499 $ — $ 323,227 Liabilities: Series 1 nonconvertible preferred stock — — 1,628 1,628 $ — $ — $ 1,628 $ 1,628 Fair Value Measurements at September 30, 2017 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 19,863 $ — $ — $ 19,863 Commercial paper — 29,756 — 29,756 Corporate bonds — 3,000 — 3,000 Marketable securities: U.S. Treasury notes 60,843 — — 60,843 Corporate bonds — 150,731 — 150,731 Commercial paper — 12,458 — 12,458 U.S. Agency bonds — 4,000 — 4,000 $ 80,706 $ 199,945 $ — $ 280,651 Liabilities: Warrant liability $ — $ — $ 807 $ 807 Series 1 nonconvertible preferred stock — — 762 762 $ — $ — $ 1,569 $ 1,569 Cash equivalents at September 30, 2018 and 2017 consist of money market funds, corporate bonds and commercial paper which are readily convertible to cash and with less than 90 days until maturity. During the years ended September 30, 2018, 2017, and 2016, there were no transfers between Level 1, Level 2 and Level 3. As of September 30, 2017, the Company’s warrant liability was comprised of the value of warrants for the purchase of its Series 1 nonconvertible preferred stock. These warrants were financial instruments that might have required a transfer of assets because of the liquidation features in the contract and were therefore recorded as liabilities and measured at fair value. These warrants expired on October 4, 2017, and are therefore no longer outstanding. The outstanding shares of Series 1 nonconvertible preferred stock a s of September 30, 2018 and 2017 were also measured at fair value. The fair values of both of these instruments were 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 values of the warrant liability and 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 warrant liability and Series 1 nonconvertible preferred stock using probability-weighted discounted cash flow include the following significant unobservable inputs: Range (Weighted Average) September 30, Unobservable Input 2018 2017 Probabilities of payout 0%-70% 0%-65% Discount rate 6.25% 5.25% The following table provides a rollforward of the aggregate fair values of the Company’s warrants for the purchase of Series 1 nonconvertible preferred stock and the outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs: Warrant Liability Series 1 Nonconvertible Preferred Stock (in thousands) Balance, September 30, 2015 $ 1,276 $ 163 Decrease in fair value (25 ) (4 ) Balance, September 30, 2016 1,251 159 Warrants exercised (549 ) 549 Increase in fair value 105 54 Balance, September 30, 2017 807 762 Warrants exercised (766 ) 766 Warrants expired (41 ) — Increase in fair value — 100 Balance, September 30, 2018 $ — $ 1,628

Marketable Securities

Marketable Securities	12 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Marketable Securities	4. Marketable Securities As of September 30, 2018 and 2017, the fair value of available-for-sale marketable securities, by type of security, was as follows: September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Commercial paper $ 113,885 $ — $ — $ 113,885 Corporate bonds 105,105 1 (477 ) 104,629 U.S. Treasury notes 42,801 — (98 ) 42,703 $ 261,791 $ 1 $ (575 ) $ 261,217 September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate bonds $ 150,841 $ 9 $ (119 ) $ 150,731 U.S. Treasury notes 60,908 — (65 ) 60,843 Commercial paper 12,458 — — 12,458 U.S. Agency bonds 4,004 — (4 ) 4,000 $ 228,211 $ 9 $ (188 ) $ 228,032 As of September 30, 2018 and 2017, 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 $16,389 and $70,038, respectively.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Sep. 30, 2018
Property Plant And Equipment [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consisted of the following as of September 30, 2018 and 2017: September 30, 2018 2017 (in thousands) Laboratory and office equipment $ 11,110 $ 9,521 Leasehold improvements 3,739 3,717 Purchased software 1,039 775 Furniture 630 595 Computer equipment 331 245 Construction in progress 617 250 17,466 15,103 Less: Accumulated depreciation and amortization (9,092 ) (7,054 ) $ 8,374 $ 8,049 Depreciation and amortization expense for property and equipment, including assets acquired under capital leases, was $2,518, $2,137 and $1,661 for the years ended September 30, 2018, 2017, and 2016, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities	12 Months Ended
	Sep. 30, 2018
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities	6. Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities Accrued expenses and other current liabilities and other long-term liabilities consisted of the following as of September 30, 2018 and 2017: September 30, 2018 2017 Accrued expenses and other current liabilities: (in thousands) Accrued preclinical and clinical expenses $ 3,617 $ 3,156 Accrued payroll and related expenses 3,274 2,829 Accrued vendor manufacturing 1,901 1,130 Accrued professional fees 507 456 Accrued other 593 399 $ 9,892 $ 7,970 Other long-term liabilities: Uncertain tax positions $ 1,792 $ 1,175 Accrued rent expense 593 676 Capital lease obligation 293 379 Asset retirement obligation 217 180 $ 2,895 $ 2,410

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	7. Collaboration Agreements AbbVie Collaboration On November 27, 2006, the Company entered into a Collaborative Development and License Agreement (the “AbbVie Agreement”) with Abbott Laboratories to identify, develop and commercialize HCV NS3 and NS3/4A protease inhibitor compounds, including paritaprevir and glecaprevir. The agreement was assigned by Abbott to AbbVie Inc. on January 1, 2013 in connection with Abbott’s transfer of its research-based pharmaceuticals business to AbbVie. Under the terms of the AbbVie Agreement, as amended, AbbVie paid the Company upfront license payments and FTE reimbursements to fund research activities. The Company is also eligible to receive milestone payments for the successful development by AbbVie of one or more HCV compounds, as well as annually tiered, per-product royalties on the portion of AbbVie’s net sales of its HCV treatment regimens allocated to the protease inhibitor product. The Company determined that the deliverables under the AbbVie Agreement included (i) the non-exclusive, royalty-free, worldwide research license and the exclusive, royalty-bearing development and commercialization license, (ii) the research services, and (iii) a commitment to participate on a steering committee, all of which were to be delivered over a three-year period. The Company concluded that the license did not have standalone value as it was dependent, in part, upon the Company’s continuing involvement in the HCV protease inhibitor research and its involvement in the joint steering committee. Additionally, the undelivered items, including the Company’s participation in the joint steering committee, which was considered participatory due to its decision making responsibilities, and the research services, did not have VSOE or VOE of fair value. Therefore, the license, the research services, and the joint steering committee participation were treated as a single unit of accounting. Accordingly, all amounts received were deferred, and revenue was recognized using the proportional performance model over the period during which the Company performed research services in connection with the AbbVie Agreement, as amended. Subsequent to the research and evaluation period, which ended in June 2011, all decisions related to the development, commercialization and marketing have been made by AbbVie. The Company has the right to continue to attend the joint steering committee meetings to monitor the development and marketing plans; however, the Company has no decision-making rights. As such, the joint steering committee commitment became protective in nature as of June 16, 2011. During the years ended September 30, 2018, 2017, and 2016, the Company received $15,000, $65,000, and $30,000, respectively, in milestone payments under the AbbVie Agreement as a result of AbbVie’s commercialization regulatory approvals. From commencement of the collaboration through September 30, 2018 the Company has received an upfront license payment, research funding, milestone payments, and preferred stock financing totaling $396,000 under the AbbVie agreement The Company is also receiving annually tiered royalties per Company protease product ranging from ten percent up to twenty percent, or on a blended basis from the low double digits 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 product 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. The following table details the royalty tiers associated with cumulative calendar year net sales allocated to each royalty-bearing product as provided in the AbbVie Agreement: Calendar Year Net Sales Royalty Tier (in thousands) (%) up to $500,000 10% from $500,000 up to $750,000 12% from $750,000 up to $1,000,000 14% from $1,000,000 up to $2,500,000 17% greater than or equal to $2,500,000 20% Royalties owed to the Company under the agreement can be reduced by AbbVie in certain circumstances, including (i) if AbbVie exercises its right to license or otherwise acquire rights to intellectual property controlled by a third party where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, (ii) where a product developed under the collaboration agreement is sold in a country and not covered by a valid patent claim in such country, and (iii) where sales of a generic product are equal to at least a specified percentage of AbbVie’s market share of its product in a country. AbbVie’s obligation to pay royalties on a product developed under the agreement expires on a country-by-country basis upon the later of (i) the date of expiration of the last of the licensed patents with a valid claim covering the product in the applicable country, or (ii) ten years after the first commercial sale of the product in the applicable country. Subject to certain exceptions, a party’s rights and obligations under the agreement continue until (i) such time as AbbVie is no longer developing a product candidate or (ii) if, as of the time AbbVie is no longer developing any product candidates, AbbVie is commercializing any other protease inhibitor product, such time as all royalty terms for all covered products have ended. Accordingly, the final expiration date of the agreement is currently indeterminable. Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice. If the Company terminates the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted the Company (i) a non-exclusive, perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate, and (ii) an exclusive (even as to AbbVie), perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in any joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds. Upon the Company’s request, AbbVie will also transfer to the Company all right, title and interest in any related product trademarks, regulatory filings and clinical trials. If AbbVie terminates the agreement for the Company’s uncured breach, the milestone and royalty payments payable by AbbVie may be reduced, the licenses granted to AbbVie will remain in place, the Company will be deemed to have granted AbbVie an exclusive license under the Company’s interest in joint intellectual property, AbbVie will continue to have the right to commercialize any covered products, and all rights and licenses granted to the Company by AbbVie will terminate. NIAID Contract On September 30, 2011, the Company entered into a contract with the National Institute of Allergy and Infectious Diseases (“NIAID”), a division of the National Institutes of Health (“NIH”), providing development funding to the Company for the preclinical and clinical development of a bridged bicyclic antibiotic. The contract was completed in August 2015 upon the Company’s delivery of the study report for the Phase 1 clinical study. The Company recognized revenue under this contract as development services were performed in accordance with the funding agreement. During the year ended September 30, 2016, the Company recognized revenue of $576 under this contract. The Company received aggregate payments of $20,637 under the NIAID contract from its commencement through January 31, 2016.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity The Company is authorized to issue 100,000 shares of common stock at a par value of $0.01. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive such dividends as may be declared by the board of directors, if any.

Series 1 Nonconvertible Preferr

Series 1 Nonconvertible Preferred Stock and Warrants	12 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Series 1 Nonconvertible Preferred Stock and Warrants	9. Series 1 Nonconvertible Preferred Stock and Warrants The Company’s Certificate of Incorporation authorizes the issuance of up to 2,000 shares of Series 1 nonconvertible preferred stock at a par value of $0.01 per share. Holders of Series 1 nonconvertible preferred stock are not entitled to receive dividends. In the event of any liquidation, deemed liquidation, dissolution or winding up of the Company, the Series 1 nonconvertible preferred stockholders are entitled to receive in preference to all other stockholders, an amount equal to $1.00 per share, adjusted for any stock dividends, stock splits or reclassifications. Series 1 nonconvertible preferred stockholders will not be entitled to vote unless required by the Company pursuant to the laws of the State of Delaware. The Company may redeem the Series 1 nonconvertible preferred stock with the approval of the holders of a majority of the outstanding shares of Series 1 nonconvertible preferred stock at a redemption price of $1.00 per share. The Company must redeem the stock within 60 days of such election. Shares that are redeemed will be retired or canceled and not reissued by the Company. As these shares qualify as a derivative, they are classified as a liability on the Company’s consolidated balance sheet. In October and November 2010, a total of 2,000 warrants to purchase Series 1 nonconvertible preferred stock were issued. The warrants had an expiration date of October 4, 2017. As these warrants were free-standing financial instruments that might have required the Company to transfer assets upon exercise, up to a maximum of $2,000, these warrants were classified as liabilities on the Company’s consolidated balance sheet as of September 30, 2017. The following table summarizes the activity of the warrants to purchase Series 1 nonconvertible preferred stock: Series 1 Nonconvertible Preferred Stock Warrants Exercisable Weighted Average Exercise Price (in thousands, except per share data) Outstanding, as of September 30, 2015 1,775 $ 0.01 Granted — — Expired — — Exercised — — Outstanding, as of September 30, 2016 1,775 $ 0.01 Granted — — Expired — — Exercised (745 ) 0.01 Outstanding, as of September 30, 2017 1,030 $ 0.01 Granted — — Expired (52 ) 0.01 Exercised (978 ) 0.01 Outstanding, as of September 30, 2018 — For the years ended September 30, 2018, 2017, and 2016, the remeasurement of the warrants and Series 1 nonconvertible preferred stock resulted in other income (expense) recorded in the consolidated statements of operations of ($59), $(159), and $29, respectively. As of September 30, 2018 and 2017, the total fair value of the Series 1 nonconvertible preferred stock was $1,628 and $762, respectively. During the year ended September 30, 2018, warrants to purchase a total of 978 shares of Series 1 nonconvertible preferred stock were exercised prior to warrant expiration, resulting in the issuance of 970 shares of Series 1 nonconvertible preferred stock.

Stock-Based Awards

Stock-Based Awards	12 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Awards	10. Stock-Based Awards The Company’s 2012 Equity Incentive Plan (the “2012 Plan”) permits the Company to sell or issue awards of common stock or restricted common stock or to grant awards of incentive stock options or nonqualified stock options for the purchase of common stock, restricted stock units, performance units, stock appreciation rights or other cash incentive awards, to employees, members of the board of directors and consultants of the Company. The number of shares of common stock that may be issued under the 2012 Plan is subject to increase by the number of shares forfeited under any options forfeited and not exercised under the 2012 Plan or a predecessor plan, known as the 1995 Equity Incentive Plan, as well as by the number of shares added on the first day of each fiscal year, which is the lowest amount among the following: (i) 3% of the Company’s outstanding shares of common stock as of that date, (ii) 2,088 shares of common stock, or (iii) an amount determined by the Compensation Committee of the Board of Directors. On October 1, 2018, the number of shares of common stock that might be issued under the 2012 Plan was increased by 583 The 2012 Plan replaces and is the successor to the 1995 Equity Incentive Plan (the “1995 Plan”). The 1995 Plan provided for the Company to sell or issue awards of common stock or restricted common stock, or to grant awards of incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the board of directors and consultants of the Company. Sales, issuances or grants of shares entitle the holder to purchase common stock from the Company, for a specified exercise price, during a period specified by the applicable equity award agreement. Upon the closing of the Company’s initial public offering, all remaining shares reserved for issuance under the 1995 Plan were transferred to the 2012 Plan and no further awards were or will be made under the 1995 Plan. Under the Company’s Employee Stock Purchase Plan (“ESPP”) a total of 186 shares of common stock are reserved for issuance. As of September 30, 2018, the Company had not commenced any offering under the ESPP and no plan shares have been issued. The Company applies the fair value recognition provisions for all stock-based awards granted or modified. In the case of service-based awards, the compensation cost is recorded over the requisite service period of the award on the straight-line method based on the grant-date fair value. The requisite service period for service-based option awards is generally four years. Options granted under the 2012 Plan to employees generally vest over four years and to non-employee directors over one year, and expire after ten years. Stock Option Valuation The fair value of each stock option award is determined on the date of grant using the Black-Scholes option-pricing model. The Company estimates expected volatility based on a combination of the Company’s historical stock volatility since its March 2013 IPO and the historical volatility of publicly traded peer companies. The Company expects to continue to do so until 2019, at which time the Company will have adequate historical data regarding the volatility of the Company’s traded stock price following our March 2013 IPO. The expected term of the Company’s options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is zero on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. As required by the 1995 Plan and the 2012 Plan, the exercise price for awards granted is not to be less than the fair value of common shares as estimated by the Company as of the date of grant. The relevant data used to determine the value of the stock option awards are as follows, presented on a weighted average basis: Years Ended September 30, 2018 2017 2016 Risk-free interest rate 2.29 % 1.97 % 1.77 % Expected term (in years) 6.05 6.05 6.1 Expected volatility 57 % 60 % 70 % Expected dividends 0 % 0 % 0 % As discussed in Note 2, the Company adopted ASU 2016-09 during the year ended September 30, 2018. ASU 2016-09 intends to simplify several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity awards or liability awards, a choice to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. As a result of the adoption, the Company changed its forfeiture rate policy to recognize forfeitures as they occur. Upon adoption, the cumulative impact of this change in policy on retained earnings and deferred tax assets in the consolidated balance sheet was not material. In addition, the consolidated statements of cash flows presents excess tax benefits, if any, as part of cash flows from operating activities. The Company elected to adopt this change on a prospective basis and, therefore, excess tax benefits from prior periods in the statement of cash flow were not retroactively restated. The adoption of the standard is also expected to create variability in the consolidated statements of operations in years in which the Company is expected to have taxable income, as the tax consequences of settled share-based payments will be recognized in income tax expense when share-based payment awards are settled. The following table summarizes stock option activity, including aggregate intrinsic value for the year ended September 30, 2018: Shares Issuable Under Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term in years Aggregate Intrinsic Value (in thousands) (in thousands) Outstanding as of September 30, 2017 2,298 $ 30.36 7.4 $ 37,821 Granted 606 57.96 Exercised (229 ) 27.23 Forfeited (51 ) 48.74 Outstanding as of September 30, 2018 2,624 $ 36.65 7.1 $ 129,115 Options vested and expected to vest as of September 30, 2018 2,624 $ 36.65 7.1 $ 129,115 Options exercisable as of September 30, 2018 1,646 $ 31.84 6.2 $ 88,289 The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. The following tables summarize additional exercise and grant date information: Years Ended September 30, 2018 2017 2016 (in thousands) Aggregate intrinsic value of stock options exercised $ 14,180 $ 1,503 $ 7,705 Proceeds to Company from stock options exercised $ 6,243 $ 1,079 $ 1,026 Years Ended September 30, 2018 2017 2016 Weighted average grant date fair value of options granted (per share) $ 31.84 $ 17.52 $ 19.12 Performance-Based Options In March 2013, the Company granted to certain executives 167 options that would vest upon the achievement of certain performance-based targets. The aggregate grant date fair value of these options was $2,479. During the years ended September 30, 2017 and 2016, certain performance-based targets were achieved and the Company recorded stock-based compensation expense of $413 and $620, respectively, related to achievement of those targets. No stock-based compensation expense related to these options was recognized during the year ended September 30, 2018 as the performance period for these options ended during the year ended September 30, 2017. 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 PSUs will vest and result in issuance, or settlement, of common shares for each recipient, based upon the recipient’s continued employment with the Company through the settlement date of the award and the Company’s achievement of specified research and development milestones. The requisite service period of the PSUs is generally 2 years. The rTSRUs will vest and result in the issuance of common stock based upon the recipient’s continuing employment with the Company through the settlement date of the award and the relative ranking of the total stockholder return, or TSR, of the Company’s common stock in relation to the TSR of the component companies in the NASDAQ Biotech Index over a two-year period based on a comparison of average closing stock prices in specified periods noted in the award agreement. The number of market-based rTSRUs awarded 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% or 200% of the target number, depending on the award agreement and the year of the award. The Company used a Monte Carlo model to estimate the grant-date fair value of the rTSRUs. Assumptions and estimates utilized in the calculation of the fair value of the rTSRUs include the risk-free interest rate, dividend yield, expected volatility based on the historical volatility of publicly traded peer companies and the remaining performance period of the award. The table below sets forth the weighted average grant date fair value assumptions used to value the rTSRUs: Years Ended September 30, 2018 2017 2016 Risk-free interest rate 2.18 % 1.24 % 0.94 % Dividend yield 0 % 0 % 0 % Expected volatility 62 % 66 % 65 % Remaining performance period (years) 1.83 1.99 1.93 The following table summarizes PSU and rTSRU activity (at target) for the year ended September 30, 2018: PSUs rTSRUs Shares Weighted Average Grant Date Fair Value per Share Shares Weighted Average Grant Date Fair Value per Share (in thousands, except per share data) Unvested at September 30, 2017 70 $ 34.51 70 $ 43.07 Granted 25 77.93 25 84.70 Vested (20 ) 32.04 (25 ) 37.67 Cancelled (5 ) 32.04 — — Unvested at September 30, 2018 70 $ 50.97 70 $ 59.96 A total of 80% of target PSUs and 192.91% of target rTSRUs granted in December 2015 vested during the year ended September 30, 2018, resulting in the issuance of an aggregate of 68 common shares, net of share withholding. Restricted Stock Units In November 2016, the Company awarded restricted stock units to its employees, which vest as to 50% of the units in three years and 50% in four years, provided the employee remains employed with the Company at the time of vesting. The fair value of these awards was determined based on the intrinsic value of the stock on the date of grant and is 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 September 30, 2018: Restricted Stock Units Weighted Average Grant Date Fair Value per Share (in thousands, except per share data) Unvested at September 30, 2017 110 $ 30.00 Granted — — Vested — — Cancelled (1 ) 30.00 Unvested at September 30, 2018 109 $ 30.00 Stock-Based Compensation Expense The Company recorded the following stock-based compensation expense for the years ended September 30, 2018, 2017, and 2016: Years Ended September 30, 2018 2017 2016 (in thousands) Research and development $ 6,160 $ 4,078 $ 2,882 General and administrative 9,685 8,993 6,472 $ 15,845 $ 13,071 $ 9,354 Years Ended September 30, 2018 2017 2016 (in thousands) Stock options $ 12,694 $ 10,442 $ 8,661 rTSRUs 1,721 1,267 693 Restricted stock units 789 694 — PSUs 641 668 — $ 15,845 $ 13,071 $ 9,354 As of September 30, 2018, the Company had an aggregate of $30,064 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.2 years.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income Per Share	11. Net Income Per Share Basic and diluted net income per common share was calculated as follows for the years ended September 30, 2018, 2017, and 2016: Years Ended September 30, 2018 2017 2016 (in thousands, except per share data) Basic net income per share: Numerator: Net income $ 71,956 $ 17,710 $ 21,666 Denominator: Weighted average common shares outstanding — basic 19,255 19,066 18,929 Net income per share common share — basic $ 3.74 $ 0.93 $ 1.14 Diluted net income per share: Numerator: Net income $ 71,956 $ 17,710 $ 21,666 Denominator: Weighted average common shares outstanding — basic 19,255 19,066 18,929 Dilutive effect of common stock equivalents 1,395 341 295 Weighted average common shares outstanding — diluted 20,650 19,407 19,224 Net income per share common share — diluted $ 3.48 $ 0.91 $ 1.13 Anti-dilutive common stock equivalents excluded from above 295 2,161 1,475 The impact of certain common stock equivalents were excluded from the computation of diluted net income per common share attributable to common stockholders for the years ended September 30, 2018, 2017, and 2016, because those options had an anti-dilutive impact due to the assumed proceeds per share using the treasury stock method being greater than the average fair value of the Company’s common shares for those periods. As of September 30, 2018, 2017, and 2016, the Company excluded unvested performance stock unit awards from the calculation of diluted net income per common share as these awards contain performance conditions that would not have been achieved as of the end of each reporting period had the measurement period ended as of that date.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Leases The Company has two leases located in Watertown, Massachusetts. The first lease, for office and laboratory space at 500 Arsenal Street, was effective from fiscal 2011 to 2018. During the year ended September 30, 2015, the Company amended the lease to expand the rented space and extend the lease term through September 2022. Payment escalations specified in the lease agreement, as amended, are accrued such that rent expense is recognized on a straight-line basis over the term of occupancy. The amended lease also included a $598 tenant improvement allowance from the landlord, which was accounted for as a capital lease obligation. In connection with the 500 Arsenal Street lease, the Company has a total outstanding letter of credit in the amount of $608 as of September 30, 2018 and 2017, collateralized by a money market account. As of September 30, 2018 and 2017, the Company classified the money market account as long-term restricted cash. The second lease, for office space, located at 400 Talcott Avenue, was entered into on September 27, 2018 with a lease term that extends through August 1, 2024. The lease includes a free rent period as well as escalating rent payments over the course of the lease. The net amount of these escalations and the free rent period will be accrued and recognized as rent expense on a straight-line basis over the term of the lease. For the years ended September 30, 2018, 2017, and 2016, the Company recognized rent expense of $2,033, $2,025, and $2,025, respectively, in the consolidated statements of operations. Future minimum lease payments under both leases as of September 30, 2018 are as follows: Years Ended September 30, Operating Leases Capital Leases (in thousands) 2019 $ 2,209 $ 86 2020 2,728 93 2021 2,803 101 2022 2,684 99 2023 608 — Thereafter 519 — Total $ 11,551 $ 379 Intellectual Property Licenses In 2012 the Company entered into a non-exclusive intellectual property license agreement with a licensor of research technology under which the Company was required to pay the third party licensor an upfront license fee and additional fees up to the third anniversary of the agreement. In addition, the Company was required to pay annual maintenance fees for each year that the agreement remained in effect. During the years ended September 30, 2017 and 2016, the Company paid $115 and $120, respectively, under the agreement. The license agreement was terminated during the year ended September 30, 2017. During the year ended September 30, 2013, the Company amended an existing license agreement to extend rights to patents previously licensed for one of its programs for use in its HCV research. Under the license, the Company is obligated to pay milestones totaling up to $5,000 plus low single-digit royalties, for the development and regulatory approval of each HCV product outside of the Company’s collaboration with AbbVie and any other collaboration it may enter into in the future with a partner that has already licensed these patents. During the year ended September 30, 2016, the Company paid a $500 milestone payment under this amended agreement as a result of the Company’s filing to commence clinical development of its own HCV product candidate which was recorded as a research and development expense. further development of in 2016 and Litigation and Contingencies Related to Use of Intellectual Property From time to time, the Company may become subject to legal proceedings, claims and litigation arising in the ordinary course of business. The Company currently is not a party to any threatened or pending litigation. However, third parties might allege that the Company or its collaborators are infringing their patent rights or that the Company is otherwise violating their intellectual property rights. Such third parties may resort to litigation against the Company or its collaborators, which the Company has agreed to indemnify. With respect to some of these patents, the Company expects that it will be required to obtain licenses and could be required to pay license fees or royalties, or both. These licenses may not be available on acceptable terms, or at all. A costly license, or inability to obtain a necessary license, 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 has not accrued any liabilities related to such obligations in its financial statements as of September 30, 2018 and 2017.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes Income before income taxes for all periods presented is from domestic operations, which are the Company’s only operations. During the years ended September 30, 2018, 2017, and 2016, the Company recorded income tax expense as follows: Years Ended September 30, 2018 2017 2016 (in thousands) Current income tax (expense) benefit: Federal $ (16,449 ) $ (10,078 ) $ (12,233 ) State (2,858 ) (813 ) (956 ) Deferred income tax (expense) benefit: Federal (2,245 ) 1,503 2,136 State 387 151 159 $ (21,165 ) $ (9,237 ) $ (10,894 ) A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective tax rate is as follows: Years Ended September 30, 2018 2017 2016 Federal statutory income tax rate 24.5 % 35.0 % 35.0 % State taxes, net of federal benefit 2.6 2.7 2.7 Federal research and development tax credit (5.2 ) (7.4 ) (3.8 ) Remeasurement of net deferred tax assets 4.2 — — Share-based compensation (2.8 ) 4.5 2.6 Other (0.6 ) (0.5 ) (3.0 ) Effective income tax rate 22.7 % 34.3 % 33.5 % Net deferred tax assets as of September 30, 2018 and 2017 consisted of the following: September 30, 2018 2017 (in thousands) Deferred tax assets: Share-based compensation $ 7,372 $ 7,899 Accrued expenses 756 1,001 Capitalized research and development expenses 223 1,199 Unrealized loss 139 67 Other temporary differences 828 1,171 Total deferred tax assets 9,318 11,337 Valuation allowance — — Net deferred tax assets 9,318 11,337 Deferred tax liabilities: Depreciation (798 ) (1,026 ) Prepaid expenses (145 ) (188 ) Total deferred tax liabilities (943 ) (1,214 ) Net deferred income tax assets (liabilities) $ 8,375 $ 10,123 The net deferred tax asset is presented as a long-term asset on the consolidated balance sheets. Estimates used to prepare income tax expense are based on the Company’s initial analysis of . Given the complexity of the act, anticipated guidance from the U. S. Treasury regarding implementation of the act, and potential for additional guidance from the SEC and the Financial Accounting Standards Board related to the act, these estimates may be adjusted during fiscal 2019 to reflect any such guidance provided. While the Company believes it has adequately provided for all tax positions during the year ended September 30, 2018, amounts asserted by taxing authorities could materially differ from the Company’s accrued positions as a result of uncertain and complex application of tax law and regulations. Additionally, the recognition and measurement of certain tax benefits include estimates and judgment by management. Accordingly, the Company could record additional provisions or benefits for U.S. federal and state tax matters in future periods as new information becomes available. After consideration of all the evidence, both positive and negative, the Company determined that no valuation allowance was needed for all or a portion of its deferred tax assets as of September 30, 2018 because it is more likely than not that the deferred tax assets will be realized. In subsequent periods, the Company may determine that it is more likely than not that the deferred tax assets will not be realized and thus, a valuation allowance may be recorded against all or any portion of its deferred tax assets on the Company’s consolidated balance sheet with a corresponding non-cash charge to income tax expense in the consolidated statements of operations. 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 2014 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 financial statements. The Company is in the process of finalizing the completion of the IRS audit. 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. No adjustments have been proposed to date. The Company has not received notice of examination by any other jurisdictions for any other tax year open under statute. Uncertain tax positions 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 income tax expense. A reconciliation of the beginning and ending amount of uncertain tax positions is summarized as follows: September 30, 2018 2017 (in thousands) Beginning Balance $ 1,175 $ 745 Additions based on tax positions for the current period 563 134 Additions based on tax positions for prior periods — 355 Reductions for tax positions of prior periods (59 ) (59 ) Ending Balance $ 1,679 $ 1,175 The Company does not expect that its uncertain tax position will materially change within the next twelve months.

401(k) Plan

401(k) Plan	12 Months Ended
	Sep. 30, 2018
Postemployment Benefits [Abstract]
401(k) Plan	14. 401(k) Plan The Company has a 401(k) plan. This plan covers substantially all employees who meet minimum age and service requirements. During the years ended September 30, 2018, 2017, and 2016 the Company recognized $852, $712 and $513, respectively, of expense related to its contributions to this plan.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (unaudited)	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (unaudited)	Quarterly financial information for fiscal 2018 and 2017 is presented in the following table: 2018 Quarter Ended December 31, 2017 March 31, 2018 June 30, 2018 September 30, 2018 (in thousands, except per share data) Revenue (1) $ 38,109 $ 44,049 $ 57,262 $ 67,205 Operating expenses 23,732 27,190 34,622 32,753 Other income (expense) 960 1,066 1,338 1,429 Income tax (expense) (3,644 ) (5,370 ) (3,690 ) (8,461 ) Net income 11,693 12,555 20,288 27,420 Net income per common share — basic (3) $ 0.61 $ 0.65 $ 1.05 $ 1.41 Net income per common share — diluted (3) $ 0.59 $ 0.61 $ 0.97 $ 1.30 2017 Quarter Ended December 31, 2016 March 31, 2017 June 30, 2017 September 30, 2017 (in thousands, except per share data) Revenue (2) $ 10,417 $ 8,959 $ 7,511 $ 75,927 Operating expenses 17,463 18,465 20,640 21,632 Other income (expense) 524 549 600 660 Income tax (expense) benefit 1,542 3,565 4,103 (18,447 ) Net income (loss) (4,980 ) (5,392 ) (8,426 ) 36,508 Net income (loss) per common share — basic (3) $ (0.26 ) $ (0.28 ) $ (0.44 ) $ 1.91 Net income (loss) per common share — diluted (3) $ (0.26 ) $ (0.28 ) $ (0.44 ) $ 1.86 (1) During the first quarter of 2018, the Company recognized $15,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in Japan. (2) During the fourth quarter of 2017, the Company recognized $65,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in the U.S. and the EU (3) The earnings per share amounts for each quarter may not sum to the fiscal year amounts due to rounding and the effect of weighting.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiary, Enanta Pharmaceuticals Security Corporation, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).
Use of Estimates	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 warrants, 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.
Cash Equivalents and Marketable Securities	Cash Equivalents and Marketable Securities The Company considers all short-term, highly liquid investments with original maturities of ninety days or less at acquisition date to be cash equivalents. Marketable securities with original maturities of greater than ninety days and remaining maturities of less than one year from the balance sheet date are classified as short-term marketable securities. Marketable securities with remaining maturities of greater than one year from the balance sheet date are classified as long-term marketable securities. The Company classifies all of its marketable securities as available-for-sale. The Company continually evaluates the credit ratings of its investment portfolio and underlying securities. The Company invests in accordance with its investment policy and invests at the date of purchase in securities with a rating of A3 or higher and A- or higher according to Moody’s and S&P, respectively. The Company reports available-for-sale investments at fair value as of each balance sheet date and records any unrealized gains or losses as a component of stockholders’ equity. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense), net within the consolidated statements of operations. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate the extent to which the decline is “other than temporary” and reduces the investment to fair value through a charge to the consolidated statements of operations. There were no such adjustments necessary during the years ended September 30, 2018, 2017, and 2016.
Restricted Cash	Restricted Cash As of September 30, 2018 and 2017 the Company had an outstanding letter of credit collateralized by a money market account of $608 to the benefit of the landlord of the Company’s current building lease. This amount was classified as long-term restricted cash as of September 30, 2018 and 2017.
Concentration of Credit Risk and of Significant Customers and Suppliers	Concentration of Credit Risk and of Significant Customers and Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities and accounts receivable. The Company has all cash and investment balances at one accredited financial institution, including cash in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company has historically generated all of its revenue from its collaborative research and license agreements as well as a U.S. government contract (see Note 7). As of September 30, 2018 and 2017, accounts receivable consisted of amounts due from the Company’s principal collaborator (see Note 7). The Company is completely dependent on third-party manufacturers for product supply for preclinical and clinical research activities in its non-partnered programs. The Company relies and expects to continue to rely exclusively on several manufacturers to supply the Company with its requirements for the active pharmaceutical ingredients related to these programs. These research programs would be adversely affected by a significant interruption in the supply of its active pharmaceutical ingredients.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. A fair value hierarchy is based on three levels of inputs which are used to measure fair value, of which the first two levels are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices) such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s instruments that are carried at fair value are cash equivalents, marketable securities and the warrant and Series 1 nonconvertible preferred stock liabilities. The carrying values of accounts receivable, accounts payable and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation or amortization. Depreciation and amortization expense is recognized using the straight-line method over the following estimated useful lives: Laboratory and office equipment 5 years Leasehold improvements Shorter of life of lease or estimated useful life Purchased software 3 years Computer equipment 3 years Furniture 7 years Expenditures for repairs and maintenance of assets are charged to expense as incurred. Costs of major additions and betterments are capitalized and depreciated on a straight-line basis over their useful lives. Upon retirement or sale, the cost and related accumulated depreciation or amortization of assets disposed are removed from the accounts and any resulting gain or loss is included in income from operations in the consolidated statements of operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.
Revenue Recognition	Revenue Recognition The Company’s revenue has been generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables, which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectibility of the resulting receivable is reasonably assured, and the Company has fulfilled its performance obligations under the contract. The consideration received under multiple-element arrangements that is fixed or determinable is allocated among the separate units of accounting based on the relative selling prices of the separate units of accounting. The Company determines the selling price of a unit of accounting within each arrangement following the hierarchy of evidence prescribed by ASC 605-25 In determining the separate units of accounting, the Company evaluates whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers whether or not (i) the collaborator can use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license is dependent on the undelivered items, and (iii) the collaborator or other vendors can provide the undelivered items. For all periods presented, whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model or a straight-line model over the period of performance, which is typically the research and development term. Full-time equivalents (“FTEs”) are typically used as the measure of performance. At each reporting period, the Company reassesses its cumulative measure of performance and makes appropriate adjustments, if necessary. The Company recognizes revenue using the proportional performance model whenever the Company can make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement. Revenue recognized under the proportional performance model at each reporting period is determined by multiplying the total expected payments under the contract (excluding royalties and payments contingent upon achievement of milestones) by the ratio of the level of effort incurred to date to the estimated total level of effort required to complete the performance obligations under the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model as of each reporting period. Alternatively, if the Company cannot make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement, then revenue under the arrangement is recognized on a straight-line basis over the period expected to complete the Company’s performance obligations. If and when a contingent milestone payment is earned, the additional consideration to be received is allocated to the separate units of accounting in the arrangement based on their relative selling prices at the inception of the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined on a straight-line basis as of the period end date. If the Company cannot reasonably estimate when its performance obligation period ends, then revenue is deferred until the Company can reasonably estimate when the performance obligation period ends. Royalty revenue is recognized based on contractual terms when reported sales are reliably measurable and collectibility is reasonably assured, provided that there are no performance obligations remaining. During the year ended September 30, 2016, the Company also generated revenue from a government contract, under which the Company was reimbursed for certain allowable costs for the funded project. Revenue from the government contract was recognized when the related service was performed. The related costs incurred by the Company under the government contract were included in research and development expenses in the consolidated statements of operations. Amounts received prior to satisfying all revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the next twelve months of the consolidated balance sheet date are classified as long-term deferred revenue. In the event that a collaborative research and license agreement is terminated and the Company then has no further performance obligations, the Company recognizes as revenue any amounts that had not previously been recorded as revenue but were classified as deferred revenue at the date of such termination.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Included in research and development costs are wages, stock-based compensation and benefits of employees, third-party license fees and other operational costs related to the Company’s research and development activities, including facility-related expenses and external costs of outside contractors engaged to conduct both preclinical and clinical studies and manufacture quantities of product for preclinical and clinical studies. The Company also includes in research and development expense the costs to complete the Company’s obligations under research collaborations. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development in the period in which they are incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed.
Research and Manufacturing Contract Accruals	Research and Manufacturing Contract Accruals The Company has entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. The Company records accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research and development and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company's estimates. The Company's historical accrual estimates have not been materially different from the actual costs.
Patent Costs	Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are recorded as general and administrative expenses as incurred.
Stock-Based Compensation	Stock-Based Compensation The Company measures all stock options and other stock-based awards granted to employees at fair value on the date of grant. The Company uses the Black-Scholes option-pricing model in the valuation of its stock options. The fair value of performance-based awards and restricted stock units is based on intrinsic value of the stock on the date of grant. The Company uses the Monte-Carlo model in order to calculate the fair value of the market-based awards. The fair value of options is recognized as stock-based compensation expense over the requisite service period, which is generally the vesting period of the respective award. Commencing with the adoption of ASU No. 2016-09 on October 1, 2017, t
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. Uncertain tax positions represent tax positions for which reserves have been established. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely than not to be sustained, the tax position is then assessed to determine the amount of benefit to be recognized in the financial statements. The amount that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. Income tax expense includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.
Net Income per Share	Net Income per Share Basic net income per common share is computed by dividing the net income by the weighted average number of shares of common stock outstanding for the period. Diluted net income per common share is computed by dividing net income 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. Market-based awards are included in diluted net income per common share to the extent they would have vested if the period end date was the market criteria measurement date.
Segment Data	Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is a biotechnology company focused on discovering and developing small molecule drugs for the treatment of viral infections and liver diseases. Revenue is generated exclusively from transactions occurring with partners located in the United States and all assets are held in the United States.
Comprehensive Income	Comprehensive Income Comprehensive income includes net income as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income is unrealized gains and losses on available-for-sale marketable securities.
Going Concern	Going Concern In August 2014, the Financial Accounting Standards Board (the “ Presentation of Financial Statements - Going Concern (Subtopic 205-40) . Based on a detailed cash forecast incorporating current research and development activities and related spending plans, the Company believes that current cash, cash equivalents and marketable securities on hand at September 30, 2018 should be sufficient to fund operations for the foreseeable future, including at least the next twelve months beyond the date of issuance of these financial statements. The amount of capital available will depend on the Company’s management of its existing cash, cash equivalents and marketable securities, as well as the level of future royalties the Company earns under its agreement with AbbVie. If the Company should require financing beyond these resources to fund its research and development efforts, it may not be able to obtain financing on acceptable terms, or at all.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), which intends to simplify several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, a choice to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. This amendment was effective for the Company in the fiscal year beginning October 1, 2017. As a result of the adoption, the Company changed its forfeiture rate policy to recognize forfeitures as they occur. Upon adoption, the cumulative impact of this accounting policy change on retained earnings, additional paid-in capital and deferred tax assets in the consolidated balance sheet was not material. In addition, the consolidated statements of cash flows now presents excess tax benefits as part of cash flows from operating activities. The Company elected to adopt this change on a prospective basis and, therefore, excess tax benefits from prior periods in the consolidated statements of cash flow were not restated. The adoption of the standard is also expected to create variability in the consolidated statements of operations in years in which the Company is expected to have taxable income, as the tax consequences of settled share-based payments will be recognized in income tax expense when share-based payment awards are settled. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”) which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. The FASB has continued to issue accounting standards updates to clarify and provide implementation guidance related to Revenue from Contracts with Customers, including ASU 2016-08 , Revenue from Contract with Customers: Principal versus Agent Considerations , ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing , and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. These amendments address a number of areas, including an entity’s identification of its performance obligations in a contract, collectibility, non-cash consideration, presentation of sales tax and an entity’s evaluation of the nature of its promise to grant a license of intellectual property and whether or not that revenue is recognized over time or at a point in time. The new guidance must be adopted using either a modified retrospective approach or a full retrospective approach for all periods presented. Under the modified retrospective method, the cumulative effect of applying the new standard would be recognized at the adoption date in retained earnings on the consolidated balance sheet. Under the full retrospective approach, the new standard would be applied to each prior reporting period presented. These new standards will be effective for the Company beginning October 1, 2018. The Company will adopt the standard under the modified retrospective method, the impact of which is not expected to have a material impact on the Company’s consolidated financial statements as the AbbVie Agreement is the only revenue-generating arrangement outstanding and all performance obligations under the agreement have been completed by the end of fiscal 2011. The adoption of ASU 2014-09 did not have an impact on the Company’s accounting for contingent milestone or royalty payments. All contingent milestone payments earned since fiscal 2011 have been recognized as revenue when the associated milestone was achieved by AbbVie . The Company is currently earning annually tiered per-product royalties on the portion of AbbVie’s net sales of its HCV regimens allocable to the protease inhibitor product in the regimen. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”) that changes the presentation of restricted cash and cash equivalents on the statement of cash flows. Restricted cash and restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. Upon adoption, the Company will adjust the presentation of the statement of cash flows to include restricted cash related to an outstanding letter of credit collateralized by a money market fund of $608 so that it is included in the balances of cash and cash equivalents. In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718) (“ASU 2017-09”) which This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which will replace the existing guidance in ASC 840, “Leases.” The updated standard aims to increase transparency and comparability among organizations by requiring lessees to recognize leased assets and leased liabilities on the consolidated balance sheets and requiring disclosure of key information about leasing arrangements. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2016-02 may have on its financial position and results of operations. 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 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. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2017-08 may have on its financial position and results of operations. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (“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. 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 .

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Property and Equipment Estimated Useful Lives	Property and equipment are stated at cost less accumulated depreciation or amortization. Depreciation and amortization expense is recognized using the straight-line method over the following estimated useful lives: Laboratory and office equipment 5 years Leasehold improvements Shorter of life of lease or estimated useful life Purchased software 3 years Computer equipment 3 years Furniture 7 years

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	12 Months Ended
	Sep. 30, 2018
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 September 30, 2018 and 2017 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value: Fair Value Measurements at September 30, 2018 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 51,025 $ — $ — $ 51,025 Commercial paper — 6,987 — 6,987 Corporate bonds — 3,998 — 3,998 Marketable securities: U.S. Treasury notes 42,703 — — 42,703 Commercial paper — 113,885 — 113,885 Corporate bonds — 104,629 — 104,629 $ 93,728 $ 229,499 $ — $ 323,227 Liabilities: Series 1 nonconvertible preferred stock — — 1,628 1,628 $ — $ — $ 1,628 $ 1,628 Fair Value Measurements at September 30, 2017 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds $ 19,863 $ — $ — $ 19,863 Commercial paper — 29,756 — 29,756 Corporate bonds — 3,000 — 3,000 Marketable securities: U.S. Treasury notes 60,843 — — 60,843 Corporate bonds — 150,731 — 150,731 Commercial paper — 12,458 — 12,458 U.S. Agency bonds — 4,000 — 4,000 $ 80,706 $ 199,945 $ — $ 280,651 Liabilities: Warrant liability $ — $ — $ 807 $ 807 Series 1 nonconvertible preferred stock — — 762 762 $ — $ — $ 1,569 $ 1,569
Fair Value Measurements of the Company's Warrant Liability and Series 1 Nonconvertible Preferred Stock	The recurring Level 3 fair value measurements of the Company’s warrant liability and Series 1 nonconvertible preferred stock using probability-weighted discounted cash flow include the following significant unobservable inputs: Range (Weighted Average) September 30, Unobservable Input 2018 2017 Probabilities of payout 0%-70% 0%-65% Discount rate 6.25% 5.25%
Rollforward of Aggregate Fair Values of Warrants and Outstanding Series 1 Nonconvertible Preferred Stock	The following table provides a rollforward of the aggregate fair values of the Company’s warrants for the purchase of Series 1 nonconvertible preferred stock and the outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs: Warrant Liability Series 1 Nonconvertible Preferred Stock (in thousands) Balance, September 30, 2015 $ 1,276 $ 163 Decrease in fair value (25 ) (4 ) Balance, September 30, 2016 1,251 159 Warrants exercised (549 ) 549 Increase in fair value 105 54 Balance, September 30, 2017 807 762 Warrants exercised (766 ) 766 Warrants expired (41 ) — Increase in fair value — 100 Balance, September 30, 2018 $ — $ 1,628

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Fair Value of Available-for-Sale Marketable Securities by Type of Security	As of September 30, 2018 and 2017, the fair value of available-for-sale marketable securities, by type of security, was as follows: September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Commercial paper $ 113,885 $ — $ — $ 113,885 Corporate bonds 105,105 1 (477 ) 104,629 U.S. Treasury notes 42,801 — (98 ) 42,703 $ 261,791 $ 1 $ (575 ) $ 261,217 September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate bonds $ 150,841 $ 9 $ (119 ) $ 150,731 U.S. Treasury notes 60,908 — (65 ) 60,843 Commercial paper 12,458 — — 12,458 U.S. Agency bonds 4,004 — (4 ) 4,000 $ 228,211 $ 9 $ (188 ) $ 228,032

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Sep. 30, 2018
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following as of September 30, 2018 and 2017: September 30, 2018 2017 (in thousands) Laboratory and office equipment $ 11,110 $ 9,521 Leasehold improvements 3,739 3,717 Purchased software 1,039 775 Furniture 630 595 Computer equipment 331 245 Construction in progress 617 250 17,466 15,103 Less: Accumulated depreciation and amortization (9,092 ) (7,054 ) $ 8,374 $ 8,049

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities (Tables)	12 Months Ended
	Sep. 30, 2018
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities	Accrued expenses and other current liabilities and other long-term liabilities consisted of the following as of September 30, 2018 and 2017: September 30, 2018 2017 Accrued expenses and other current liabilities: (in thousands) Accrued preclinical and clinical expenses $ 3,617 $ 3,156 Accrued payroll and related expenses 3,274 2,829 Accrued vendor manufacturing 1,901 1,130 Accrued professional fees 507 456 Accrued other 593 399 $ 9,892 $ 7,970 Other long-term liabilities: Uncertain tax positions $ 1,792 $ 1,175 Accrued rent expense 593 676 Capital lease obligation 293 379 Asset retirement obligation 217 180 $ 2,895 $ 2,410

Collaboration Agreements (Table

Collaboration Agreements (Tables)	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Royalty Tiers Associated with Cumulative Calendar Year Net Sales Allocated to Each Royalty-bearing Product	The following table details the royalty tiers associated with cumulative calendar year net sales allocated to each royalty-bearing product as provided in the AbbVie Agreement: Calendar Year Net Sales Royalty Tier (in thousands) (%) up to $500,000 10% from $500,000 up to $750,000 12% from $750,000 up to $1,000,000 14% from $1,000,000 up to $2,500,000 17% greater than or equal to $2,500,000 20%

Series 1 Nonconvertible Prefe_2

Series 1 Nonconvertible Preferred Stock and Warrants (Tables)	12 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Summary of Activity of the Warrants to Purchase Series 1 Nonconvertible Preferred Stock	The following table summarizes the activity of the warrants to purchase Series 1 nonconvertible preferred stock: Series 1 Nonconvertible Preferred Stock Warrants Exercisable Weighted Average Exercise Price (in thousands, except per share data) Outstanding, as of September 30, 2015 1,775 $ 0.01 Granted — — Expired — — Exercised — — Outstanding, as of September 30, 2016 1,775 $ 0.01 Granted — — Expired — — Exercised (745 ) 0.01 Outstanding, as of September 30, 2017 1,030 $ 0.01 Granted — — Expired (52 ) 0.01 Exercised (978 ) 0.01 Outstanding, as of September 30, 2018 —

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	12 Months Ended
	Sep. 30, 2018
Data Used to Determine Value of Stock Option Grants, Presented on Weighted Average Basis	The relevant data used to determine the value of the stock option awards are as follows, presented on a weighted average basis: Years Ended September 30, 2018 2017 2016 Risk-free interest rate 2.29 % 1.97 % 1.77 % Expected term (in years) 6.05 6.05 6.1 Expected volatility 57 % 60 % 70 % Expected dividends 0 % 0 % 0 %
Stock Option Activity	The following table summarizes stock option activity, including aggregate intrinsic value for the year ended September 30, 2018: Shares Issuable Under Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term in years Aggregate Intrinsic Value (in thousands) (in thousands) Outstanding as of September 30, 2017 2,298 $ 30.36 7.4 $ 37,821 Granted 606 57.96 Exercised (229 ) 27.23 Forfeited (51 ) 48.74 Outstanding as of September 30, 2018 2,624 $ 36.65 7.1 $ 129,115 Options vested and expected to vest as of September 30, 2018 2,624 $ 36.65 7.1 $ 129,115 Options exercisable as of September 30, 2018 1,646 $ 31.84 6.2 $ 88,289
Summary of Additional Exercise and Grant Date Information	The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. The following tables summarize additional exercise and grant date information: Years Ended September 30, 2018 2017 2016 (in thousands) Aggregate intrinsic value of stock options exercised $ 14,180 $ 1,503 $ 7,705 Proceeds to Company from stock options exercised $ 6,243 $ 1,079 $ 1,026 Years Ended September 30, 2018 2017 2016 Weighted average grant date fair value of options granted (per share) $ 31.84 $ 17.52 $ 19.12
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock unit activity for the year to date period ending September 30, 2018: Restricted Stock Units Weighted Average Grant Date Fair Value per Share (in thousands, except per share data) Unvested at September 30, 2017 110 $ 30.00 Granted — — Vested — — Cancelled (1 ) 30.00 Unvested at September 30, 2018 109 $ 30.00
Stock-Based Compensation Expense	The Company recorded the following stock-based compensation expense for the years ended September 30, 2018, 2017, and 2016: Years Ended September 30, 2018 2017 2016 (in thousands) Research and development $ 6,160 $ 4,078 $ 2,882 General and administrative 9,685 8,993 6,472 $ 15,845 $ 13,071 $ 9,354 Years Ended September 30, 2018 2017 2016 (in thousands) Stock options $ 12,694 $ 10,442 $ 8,661 rTSRUs 1,721 1,267 693 Restricted stock units 789 694 — PSUs 641 668 — $ 15,845 $ 13,071 $ 9,354
Relative Total Stockholder Return Units [Member]
Data Used to Determine Value of Stock Option Grants, Presented on Weighted Average Basis	. The table below sets forth the weighted average grant date fair value assumptions used to value the rTSRUs: Years Ended September 30, 2018 2017 2016 Risk-free interest rate 2.18 % 1.24 % 0.94 % Dividend yield 0 % 0 % 0 % Expected volatility 62 % 66 % 65 % Remaining performance period (years) 1.83 1.99 1.93
Performance Share Units and Relative Total Stockholder Return Units [Member]
Summary of PSUs and rTSRUs Activity	The following table summarizes PSU and rTSRU activity (at target) for the year ended September 30, 2018: PSUs rTSRUs Shares Weighted Average Grant Date Fair Value per Share Shares Weighted Average Grant Date Fair Value per Share (in thousands, except per share data) Unvested at September 30, 2017 70 $ 34.51 70 $ 43.07 Granted 25 77.93 25 84.70 Vested (20 ) 32.04 (25 ) 37.67 Cancelled (5 ) 32.04 — — Unvested at September 30, 2018 70 $ 50.97 70 $ 59.96

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Basic and Diluted Net Income Per Common Share	Basic and diluted net income per common share was calculated as follows for the years ended September 30, 2018, 2017, and 2016: Years Ended September 30, 2018 2017 2016 (in thousands, except per share data) Basic net income per share: Numerator: Net income $ 71,956 $ 17,710 $ 21,666 Denominator: Weighted average common shares outstanding — basic 19,255 19,066 18,929 Net income per share common share — basic $ 3.74 $ 0.93 $ 1.14 Diluted net income per share: Numerator: Net income $ 71,956 $ 17,710 $ 21,666 Denominator: Weighted average common shares outstanding — basic 19,255 19,066 18,929 Dilutive effect of common stock equivalents 1,395 341 295 Weighted average common shares outstanding — diluted 20,650 19,407 19,224 Net income per share common share — diluted $ 3.48 $ 0.91 $ 1.13 Anti-dilutive common stock equivalents excluded from above 295 2,161 1,475

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Future minimum lease payments under both leases as of September 30, 2018 are as follows: Years Ended September 30, Operating Leases Capital Leases (in thousands) 2019 $ 2,209 $ 86 2020 2,728 93 2021 2,803 101 2022 2,684 99 2023 608 — Thereafter 519 — Total $ 11,551 $ 379

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Summary of Income Tax Expense	During the years ended September 30, 2018, 2017, and 2016, the Company recorded income tax expense as follows: Years Ended September 30, 2018 2017 2016 (in thousands) Current income tax (expense) benefit: Federal $ (16,449 ) $ (10,078 ) $ (12,233 ) State (2,858 ) (813 ) (956 ) Deferred income tax (expense) benefit: Federal (2,245 ) 1,503 2,136 State 387 151 159 $ (21,165 ) $ (9,237 ) $ (10,894 )
Reconciliation of Income Tax Provision at Federal Statutory Income Tax Rate and Effective Tax Rate	A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective tax rate is as follows: Years Ended September 30, 2018 2017 2016 Federal statutory income tax rate 24.5 % 35.0 % 35.0 % State taxes, net of federal benefit 2.6 2.7 2.7 Federal research and development tax credit (5.2 ) (7.4 ) (3.8 ) Remeasurement of net deferred tax assets 4.2 — — Share-based compensation (2.8 ) 4.5 2.6 Other (0.6 ) (0.5 ) (3.0 ) Effective income tax rate 22.7 % 34.3 % 33.5 %
Net Deferred Tax Assets and Liabilities	Net deferred tax assets as of September 30, 2018 and 2017 consisted of the following: September 30, 2018 2017 (in thousands) Deferred tax assets: Share-based compensation $ 7,372 $ 7,899 Accrued expenses 756 1,001 Capitalized research and development expenses 223 1,199 Unrealized loss 139 67 Other temporary differences 828 1,171 Total deferred tax assets 9,318 11,337 Valuation allowance — — Net deferred tax assets 9,318 11,337 Deferred tax liabilities: Depreciation (798 ) (1,026 ) Prepaid expenses (145 ) (188 ) Total deferred tax liabilities (943 ) (1,214 ) Net deferred income tax assets (liabilities) $ 8,375 $ 10,123
Schedule of Reconciliation of Uncertain Tax Positions	A reconciliation of the beginning and ending amount of uncertain tax positions is summarized as follows: September 30, 2018 2017 (in thousands) Beginning Balance $ 1,175 $ 745 Additions based on tax positions for the current period 563 134 Additions based on tax positions for prior periods — 355 Reductions for tax positions of prior periods (59 ) (59 ) Ending Balance $ 1,679 $ 1,175

Selected Quarterly Financial _2

Selected Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Quarterly financial information for fiscal 2018 and 2017 is presented in the following table: 2018 Quarter Ended December 31, 2017 March 31, 2018 June 30, 2018 September 30, 2018 (in thousands, except per share data) Revenue (1) $ 38,109 $ 44,049 $ 57,262 $ 67,205 Operating expenses 23,732 27,190 34,622 32,753 Other income (expense) 960 1,066 1,338 1,429 Income tax (expense) (3,644 ) (5,370 ) (3,690 ) (8,461 ) Net income 11,693 12,555 20,288 27,420 Net income per common share — basic (3) $ 0.61 $ 0.65 $ 1.05 $ 1.41 Net income per common share — diluted (3) $ 0.59 $ 0.61 $ 0.97 $ 1.30 2017 Quarter Ended December 31, 2016 March 31, 2017 June 30, 2017 September 30, 2017 (in thousands, except per share data) Revenue (2) $ 10,417 $ 8,959 $ 7,511 $ 75,927 Operating expenses 17,463 18,465 20,640 21,632 Other income (expense) 524 549 600 660 Income tax (expense) benefit 1,542 3,565 4,103 (18,447 ) Net income (loss) (4,980 ) (5,392 ) (8,426 ) 36,508 Net income (loss) per common share — basic (3) $ (0.26 ) $ (0.28 ) $ (0.44 ) $ 1.91 Net income (loss) per common share — diluted (3) $ (0.26 ) $ (0.28 ) $ (0.44 ) $ 1.86 (1) During the first quarter of 2018, the Company recognized $15,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in Japan. (2) During the fourth quarter of 2017, the Company recognized $65,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in the U.S. and the EU (3) The earnings per share amounts for each quarter may not sum to the fiscal year amounts due to rounding and the effect of weighting.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Summary of Accounting and Financial Policies [Line Items]
Adjustment to fair value	$ 0	$ 0	$ 0
Cash and investment restricted as a collateral for outstanding letter of credit	608,000	608,000
ASU 2016-18 [Member]
Summary of Accounting and Financial Policies [Line Items]
Outstanding letter of credit	608,000
Money Market Funds [Member]
Summary of Accounting and Financial Policies [Line Items]
Cash and investment restricted as a collateral for outstanding letter of credit	$ 608,000	$ 608,000
Maximum [Member]
Summary of Accounting and Financial Policies [Line Items]
Short-term investments maturity period	90 days
Short-term marketable securities maturity period	1 year
Minimum [Member]
Summary of Accounting and Financial Policies [Line Items]
Short-term marketable securities maturity period	90 days
Long-term marketable securities maturity period	1 year
Income tax benefit recognition, percentage of likelihood of being realized upon settlement	50.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Property and Equipment Estimated Useful Lives (Detail)	12 Months Ended
	Sep. 30, 2018
Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements useful life	Shorter of life of lease or estimated useful life
Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	7 years

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	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Assets:
Assets, Fair Value Disclosure, Total	$ 323,227	$ 280,651
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,628	1,569
Warrant Liability [Member]
Liabilities:
Liabilities		807	$ 1,251	$ 1,276
Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,628	762	$ 159	$ 163
Level 1 [Member]
Assets:
Assets, Fair Value Disclosure, Total	93,728	80,706
Level 2 [Member]
Assets:
Assets, Fair Value Disclosure, Total	229,499	199,945
Level 3 [Member]
Liabilities:
Liabilities, Fair Value Disclosure, Total	1,628	1,569
Level 3 [Member] | Warrant Liability [Member]
Liabilities:
Liabilities		807
Level 3 [Member] | Series 1 Nonconvertible Preferred Stock [Member]
Liabilities:
Liabilities	1,628	762
U.S. Treasury Notes [Member]
Assets:
Marketable securities	42,703	60,843
U.S. Treasury Notes [Member] | Level 1 [Member]
Assets:
Marketable securities	42,703	60,843
Money Market Funds [Member]
Assets:
Cash equivalents	51,025	19,863
Money Market Funds [Member] | Level 1 [Member]
Assets:
Cash equivalents	51,025	19,863
Corporate Bonds [Member]
Assets:
Cash equivalents	3,998	3,000
Marketable securities	104,629	150,731
Corporate Bonds [Member] | Level 2 [Member]
Assets:
Cash equivalents	3,998	3,000
Marketable securities	104,629	150,731
Commercial Paper [Member]
Assets:
Cash equivalents	6,987	29,756
Marketable securities	113,885	12,458
Commercial Paper [Member] | Level 2 [Member]
Assets:
Cash equivalents	6,987	29,756
Marketable securities	$ 113,885	12,458
U.S. Agency Bonds [Member]
Assets:
Marketable securities		4,000
U.S. Agency Bonds [Member] | Level 2 [Member]
Assets:
Marketable securities		$ 4,000

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0	$ 0
Warrant expiration date	Oct. 4, 2017
Warrants outstanding	0

Fair Value of Financial Asset_5

Fair Value of Financial Assets and Liabilities - Fair Value Measurements of the Company's Warrant Liability and Series 1 Nonconvertible Preferred Stock (Detail) - Level 3 [Member] - Warrant Liability [Member] - Series 1 Nonconvertible Preferred Stock [Member]	Sep. 30, 2018	Sep. 30, 2017
Probabilities of Payout [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Alternative Investment, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Discount Rate [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Range (Weighted Average)	6.25	5.25
Alternative Investment, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
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)	70	65

Fair Value of Financial Asset_6

Fair Value of Financial Assets and Liabilities - Rollforward of Aggregate Fair Values of Warrants (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Series 1 Nonconvertible Preferred Stock [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 762	$ 159	$ 163
Warrants exercised	766	549
Increase (Decrease) in fair value	100	54	(4)
Ending Balance	1,628	762	159
Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	807	1,251	1,276
Warrants exercised	(766)	(549)
Warrants expired	$ (41)
Increase (Decrease) in fair value		105	(25)
Ending Balance		$ 807	$ 1,251

Marketable Securities - Fair Va

Marketable Securities - Fair Value of Available-for-Sale Marketable Securities by Type of Security (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 261,791	$ 228,211
Gross Unrealized Gains	1	9
Gross Unrealized Losses	(575)	(188)
Fair Value	261,217	228,032
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	105,105	150,841
Gross Unrealized Gains	1	9
Gross Unrealized Losses	(477)	(119)
Fair Value	104,629	150,731
U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	42,801	60,908
Gross Unrealized Losses	(98)	(65)
Fair Value	42,703	60,843
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	113,885	12,458
Fair Value	$ 113,885	12,458
U.S. Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		4,004
Gross Unrealized Losses		(4)
Fair Value		$ 4,000

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Marketable securities maturing in greater than one year, aggregate fair value	$ 16,389	$ 70,038
Short Term Marketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	Within one year
Long Term Marketable Securities [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	Between one and three years
Long Term Marketable Securities [Member] | U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of the marketable securities	Between one and three years

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Property and equipment	$ 17,466	$ 15,103
Less: Accumulated depreciation and amortization	(9,092)	(7,054)
Property and equipment, net	8,374	8,049
Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	11,110	9,521
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	3,739	3,717
Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	1,039	775
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	630	595
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	331	245
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 617	$ 250

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 2,518	$ 2,137	$ 1,661

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities - Accrued Expenses and Other Current Liabilities and Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Accrued expenses and other current liabilities:
Accrued preclinical and clinical expenses	$ 3,617	$ 3,156
Accrued payroll and related expenses	3,274	2,829
Accrued vendor manufacturing	1,901	1,130
Accrued professional fees	507	456
Accrued other	593	399
Accrued expenses	9,892	7,970
Other long-term liabilities:
Uncertain tax positions	1,792	1,175
Accrued rent expense	593	676
Capital lease obligation	293	379
Asset retirement obligation	217	180
Other long-term liabilities	$ 2,895	$ 2,410

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

32 Months Ended

142 Months Ended

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2018

Sep. 30, 2017

Sep. 30, 2016

Sep. 30, 2018

Sep. 30, 2018

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Revenue

$ 67,205

$ 57,262

$ 44,049

$ 38,109

$ 75,927

$ 7,511

$ 8,959

$ 10,417

$ 206,625

$ 102,814

$ 88,268

Revenue from Grants [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Revenue

576

AbbVie [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Collaboration agreement date

Nov. 27, 2006

Proceed received to fund research activities and preferred stock financing

$ 396,000

Collaboration agreement tiered royalty description

From ten percent up to twenty percent, or on a blended basis from the low double digits up to the high teens, on the portion of AbbVie’s calendar year net sales

Agreement continuation period

10 years

AbbVie [Member] | Milestone Payments [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone revenue payments received

$ 15,000

$ 65,000

30,000

National Institutes of Health, National Institute of Allergy and Infectious Diseases Contract [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Collaboration agreement date

Sep. 30, 2011

Funding received for research and development

$ 20,637

National Institutes of Health, National Institute of Allergy and Infectious Diseases Contract [Member] | Revenue from Grants [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Revenue

$ 576

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Royalty Tiers Associated with Cumulative Calendar Year Net Sales Allocated to Each Royalty-bearing Product (Detail) - AbbVie [Member]	12 Months Ended
	Sep. 30, 2018USD ($)
Up to $500,000 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	10.00%
Up to $500,000 [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 500,000,000
From $500,000 up to $750,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	12.00%
From $500,000 up to $750,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 500,000,000
From $500,000 up to $750,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 750,000,000
From $750,000 up to $1,000,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	14.00%
From $750,000 up to $1,000,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 750,000,000
From $750,000 up to $1,000,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 1,000,000,000
From $1,000,000 up to $2,500,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	17.00%
From $1,000,000 up to $2,500,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 1,000,000,000
From $1,000,000 up to $2,500,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	2,500,000,000
Greater than or equal to $2,500,000 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 2,500,000,000
Royalty Tier	20.00%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	Sep. 30, 2018	Sep. 30, 2017
Equity [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.01	$ 0.01

Series 1 Nonconvertible Prefe_3

Series 1 Nonconvertible Preferred Stock and Warrants - Additional Information (Detail) - USD ($)	Oct. 04, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Nov. 30, 2010
Class of Stock [Line Items]
Warrant expiration date		Oct. 4, 2017
Fair value of the Series 1 nonconvertible preferred stock		$ 1,628,000	$ 762,000
Expiration of outstanding warrants		52,000	0	0
Warrants to purchase total shares		978,000	745,000
Series 1 Nonconvertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Shares authorized		2,000,000
Par value of outstanding convertible preferred stock		$ 0.01
Per share value adjusted for stock dividend		1
Preferred stock redemption price per share		$ 1
Redemption period		60 days
Number of shares issuable upon exercise of the warrants	970,000				2,000,000
Warrant expiration date		Oct. 4, 2017
Transfer of assets upon exercise of warrants maximum amount					$ 2,000,000
Change in fair value of warrants		$ (59,000)	$ (159,000)	$ 29,000
Fair value of the Series 1 nonconvertible preferred stock		1,628,000	$ 762,000
Expiration of outstanding warrants	52,000
Warrants to purchase total shares	978,000
Other income from reversal of expired warrants liability		$ 41,000

Series 1 Nonconvertible Prefe_4

Series 1 Nonconvertible Preferred Stock and Warrants - Summary of Activity of the Warrants to Purchase Series 1 Nonconvertible Preferred Stock (Detail) - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Warrants And Rights Note Disclosure [Abstract]
Beginning Balance	1,030	1,775	1,775
Granted	0	0	0
Expired	(52)	0	0
Exercised	(978)	(745)
Ending Balance		1,030	1,775
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 0.01	$ 0.01	$ 0.01
Weighted Average Exercise Price Outstanding, Expired	0.01
Weighted Average Exercise Price Outstanding, Exercised	$ 0.01	0.01
Weighted Average Exercise Price Outstanding, Ending Balance		$ 0.01	$ 0.01

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 01, 2018	Nov. 30, 2016	Mar. 31, 2013	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield				0.00%	0.00%	0.00%
Compensation expenses				$ 15,845	$ 13,071	$ 9,354
Aggregate of unrecognized stock-based compensation cost				$ 30,064
Weighted average recognition period				2 years 2 months 12 days
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate of target share issued				68,000
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded				25,000
Compensation expenses				$ 641	668
Percentage of target shares vested				80.00%
Relative Total Stockholder Return Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded				25,000
Compensation expenses				$ 1,721	1,267	693
Percentage of target shares vested				192.91%
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expenses				$ 789	694
Restricted Stock Units [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Vesting percentage		50.00%
Restricted Stock Units [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
Vesting percentage		50.00%
Certain Executives [Member] | Performance-Based Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded			167,000
Aggregate grant date fair value of award			$ 2,479
Compensation expenses				$ 0	$ 413	$ 620
Certain Executives [Member] | PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, requisite service period				2 years
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, minimum				0.00%
Maximum [Member] | 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, maximum				200.00%
Minimum [Member] | 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, maximum				150.00%
2012 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of potential common stock shares to be issued				3.00%
Shares available for future grant				251,000
2012 Equity Incentive Plan [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, requisite service period				4 years
Options granted, expiration period				10 years
2012 Equity Incentive Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized	583,000
2012 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized				2,088,000
2012 Equity Incentive Plan [Member] | Maximum [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
2012 Equity Incentive Plan [Member] | Maximum [Member] | Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grant				186,000
Shares issued				0

Stock-Based Awards - Data Used

Stock-Based Awards - Data Used to Determine Value of Stock Option Grants, Presented on Weighted Average Basis (Detail)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Expected volatility	57.00%	60.00%	70.00%
Risk-free interest rate	2.29%	1.97%	1.77%
Expected term (in years)	6 years 18 days	6 years 18 days	6 years 1 month 6 days
Expected dividends	0.00%	0.00%	0.00%
Executive Officer [Member] | Relative Total Stockholder Return Units [Member]
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Expected volatility	62.00%	66.00%	65.00%
Expected term (in years)	1 year 9 months 29 days	1 year 11 months 26 days	1 year 11 months 4 days
Risk-free interest rate	2.18%	1.24%	0.94%
Expected dividends	0.00%	0.00%	0.00%

Stock-Based Awards - Stock Opti

Stock-Based Awards - Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Options
Outstanding as of beginning of period	2,298
Granted	606
Exercised	(229)
Forfeited	(51)
Outstanding as of end of period	2,624	2,298
Options vested and expected to vest as of end of period	2,624
Options exercisable as of end of period	1,646
Weighted Average Exercise Price
Outstanding	$ 30.36
Granted	57.96
Exercised	27.23
Forfeited	48.74
Outstanding	36.65	$ 30.36
Options vested and expected to vest as of end of period	36.65
Options exercisable as of end of period	$ 31.84
Weighted Average Remaining Contractual Term
Outstanding as of end of period	7 years 1 month 6 days	7 years 7 months 6 days
Options vested and expected to vest as of end period	7 years 1 month 6 days
Options exercisable as of end of period	6 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 129,115	$ 37,821
Options vested and expected to vest as of end of period	129,115
Options exercisable as of end of period	88,289
Aggregate intrinsic value of stock options exercised	14,180	1,503	$ 7,705
Proceeds to Company from stock options exercised	$ 6,243	$ 1,079	$ 1,026
Weighted average grant date fair value of options granted (per share)	$ 31.84	$ 17.52	$ 19.12

Stock-Based Awards - Summary of

Stock-Based Awards - Summary of PSUs and rTSRUs Activity (Detail) shares in Thousands	12 Months Ended
	Sep. 30, 2018$ / sharesshares
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	70
Granted | shares	25
Vested | shares	(20)
Cancelled | shares	(5)
Unvested, ending balance | shares	70
Weighted Average Grant Date Fair Value Per Share, Unvested beginning balance | $ / shares	$ 34.51
Weighted Average Grant Date Fair Value Per Share, Granted | $ / shares	77.93
Weighted Average Grant Date Fair Value Per Share, Vested | $ / shares	32.04
Weighted Average Grant Date Fair Value Per Share, Cancelled | $ / shares	32.04
Weighted Average Grant Date Fair Value Per Share, Unvested ending balance | $ / shares	$ 50.97
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	70
Granted | shares	25
Vested | shares	(25)
Unvested, ending balance | shares	70
Weighted Average Grant Date Fair Value Per Share, Unvested beginning balance | $ / shares	$ 43.07
Weighted Average Grant Date Fair Value Per Share, Granted | $ / shares	84.70
Weighted Average Grant Date Fair Value Per Share, Vested | $ / shares	37.67
Weighted Average Grant Date Fair Value Per Share, Unvested ending balance | $ / shares	$ 59.96

Stock-Based Awards - Summary _2

Stock-Based Awards - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member] shares in Thousands	12 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, beginning balance | shares	110
Cancelled | shares	(1)
Unvested, ending balance | shares	109
Weighted Average Grant Date Fair Value Per Share, Unvested beginning balance | $ / shares	$ 30
Weighted Average Grant Date Fair Value Per Share, Cancelled | $ / shares	30
Weighted Average Grant Date Fair Value Per Share, Unvested ending balance | $ / shares	$ 30

Stock-Based Awards - Stock-Base

Stock-Based Awards - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 15,845	$ 13,071	$ 9,354
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	12,694	10,442	8,661
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	641	668
rTSRUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,721	1,267	693
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	789	694
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	6,160	4,078	2,882
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 9,685	$ 8,993	$ 6,472

Net Income Per Share - Basic an

Net Income Per Share - Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Basic net income per share:
Net income	$ 27,420	$ 20,288	$ 12,555	$ 11,693	$ 36,508	$ (8,426)	$ (5,392)	$ (4,980)	$ 71,956	$ 17,710	$ 21,666
Weighted average common shares outstanding — basic									19,255	19,066	18,929
Net income per share common share — basic	$ 1.41	$ 1.05	$ 0.65	$ 0.61	$ 1.91	$ (0.44)	$ (0.28)	$ (0.26)	$ 3.74	$ 0.93	$ 1.14
Diluted net income per share:
Net income	$ 27,420	$ 20,288	$ 12,555	$ 11,693	$ 36,508	$ (8,426)	$ (5,392)	$ (4,980)	$ 71,956	$ 17,710	$ 21,666
Weighted average common shares outstanding — basic									19,255	19,066	18,929
Dilutive effect of common stock equivalents									1,395	341	295
Weighted average common shares outstanding — diluted									20,650	19,407	19,224
Net income per share common share — diluted	$ 1.30	$ 0.97	$ 0.61	$ 0.59	$ 1.86	$ (0.44)	$ (0.28)	$ (0.26)	$ 3.48	$ 0.91	$ 1.13
Anti-dilutive common stock equivalents excluded from above									295	2,161	1,475

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2018USD ($)Lease	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Commitments And Contingencies [Line Items]
Number of leases | Lease	2
Restricted cash	$ 608,000	$ 608,000
Rent expense	2,033,000	2,025,000	$ 2,025,000
Research and Development [Member]
Commitments And Contingencies [Line Items]
Company's obligation to pay	5,000,000
Milestone payment made	$ 0	0	500,000
License Agreement Terms [Member]
Commitments And Contingencies [Line Items]
License agreement, recorded liability paid		115,000	$ 120,000
First Lease [Member] | 500 Arsenal Street, Watertown, Massachusetts [Member]
Commitments And Contingencies [Line Items]
Office lease expiration period	Sep. 30, 2022
Tenant improvement allowance	$ 598,000
Outstanding letter of credit	608,000	608,000
Restricted cash	$ 608,000	$ 608,000
Second Lease [Member] | 400 Talcott Avenue, Watertown, Massachusetts [Member]
Commitments And Contingencies [Line Items]
Office lease expiration period	Aug. 1, 2024
Date of lease agreement	Sep. 27, 2018

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,019	$ 2,209
2,020	2,728
2,021	2,803
2,022	2,684
2,023	608
Thereafter	519
Total	11,551
2,019	86
2,020	93
2,021	101
2,022	99
Total	$ 379

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Current income tax (expense) benefit:
Federal									$ (16,449)	$ (10,078)	$ (12,233)
State									(2,858)	(813)	(956)
Deferred income tax (expense) benefit:
Federal									(2,245)	1,503	2,136
State									387	151	159
Total tax (expense) benefit	$ 8,461	$ 3,690	$ 5,370	$ 3,644	$ 18,447	$ (4,103)	$ (3,565)	$ (1,542)	$ (21,165)	$ (9,237)	$ (10,894)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Provision at Federal Statutory Income Tax Rate and Effective Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	24.50%	35.00%	35.00%
State taxes, net of federal benefit	2.60%	2.70%	2.70%
Federal research and development tax credit	(5.20%)	(7.40%)	(3.80%)
Remeasurement of net deferred tax assets	4.20%
Share-based compensation	(2.80%)	4.50%	2.60%
Other	(0.60%)	(0.50%)	(3.00%)
Effective income tax rate	22.70%	34.30%	33.50%

Income Taxes - Net Deferred Tax

Income Taxes - Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets:
Share-based compensation	$ 7,372	$ 7,899
Accrued expenses	756	1,001
Capitalized research and development expenses	223	1,199
Unrealized loss	139	67
Other temporary differences	828	1,171
Total deferred tax assets	9,318	11,337
Valuation allowance		0
Net deferred tax assets	9,318	11,337
Deferred tax liabilities:
Depreciation	(798)	(1,026)
Prepaid expenses	(145)	(188)
Total deferred tax liabilities	(943)	(1,214)
Net deferred income tax assets (liabilities)	$ 8,375	$ 10,123

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Beginning Balance	$ 1,175	$ 745
Additions based on tax positions for the current period	563	134
Additions based on tax positions for prior periods		355
Reductions for tax positions of prior periods	(59)	(59)
Ending Balance	$ 1,679	$ 1,175

401(k) Plan - Additional Inform

401(k) Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Compensation Related Costs [Abstract]
Benefits charged to operating expenses	$ 852	$ 712	$ 513

Selected Quarterly Financial _3

Selected Quarterly Financial Data (unaudited) - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 67,205	$ 57,262	$ 44,049	$ 38,109	$ 75,927	$ 7,511	$ 8,959	$ 10,417	$ 206,625	$ 102,814	$ 88,268
Operating expenses	32,753	34,622	27,190	23,732	21,632	20,640	18,465	17,463	118,297	78,200	57,427
Other income (expense)	1,429	1,338	1,066	960	660	600	549	524	4,793	2,333	1,719
Income tax (expense) benefit	(8,461)	(3,690)	(5,370)	(3,644)	(18,447)	4,103	3,565	1,542	21,165	9,237	10,894
Net income (loss)	$ 27,420	$ 20,288	$ 12,555	$ 11,693	$ 36,508	$ (8,426)	$ (5,392)	$ (4,980)	$ 71,956	$ 17,710	$ 21,666
Net income (loss) per common share — basic	$ 1.41	$ 1.05	$ 0.65	$ 0.61	$ 1.91	$ (0.44)	$ (0.28)	$ (0.26)	$ 3.74	$ 0.93	$ 1.14
Net income (loss) per common share — diluted	$ 1.30	$ 0.97	$ 0.61	$ 0.59	$ 1.86	$ (0.44)	$ (0.28)	$ (0.26)	$ 3.48	$ 0.91	$ 1.13

Selected Quarterly Financial _4

Selected Quarterly Financial Data (unaudited) - Schedule of Quarterly Financial Information (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Schedule Of Quarterly Financial Information [Line Items]
Revenue	$ 67,205	$ 57,262	$ 44,049	$ 38,109	$ 75,927	$ 7,511	$ 8,959	$ 10,417	$ 206,625	$ 102,814	$ 88,268
Milestone [Member]
Schedule Of Quarterly Financial Information [Line Items]
Revenue									$ 15,000	$ 65,000	$ 30,000
AbbVie [Member] | Japan [Member] | Milestone [Member]
Schedule Of Quarterly Financial Information [Line Items]
Revenue				$ 15,000
AbbVie [Member] | United States and European Union [Member] | Milestone [Member]
Schedule Of Quarterly Financial Information [Line Items]
Revenue					$ 65,000