Arrowhead Pharmaceuticals (ARWR) 10-Q 5 Aug 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2020	Jul. 27, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	ARWR
Entity Registrant Name	ARROWHEAD PHARMACEUTICALS, INC.
Entity Central Index Key	0000879407
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		102,291,803
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	001-38042
Entity Tax Identification Number	46-0408024
Entity Address, Address Line One	177 E. Colorado Blvd
Entity Address, Address Line Two	Suite 700
Entity Address, City or Town	Pasadena
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91105
City Area Code	626
Local Phone Number	304-3400
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, Par Value $0.001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Jun. 30, 2020	Sep. 30, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 219,322,617	$ 221,804,128
Accounts receivable	21,692,564	661,361
Prepaid expenses	4,096,473	3,317,999
Other current assets	2,411,937	2,563,435
Short term investments	67,709,263	36,899,894
TOTAL CURRENT ASSETS	315,232,854	265,246,817
Property and equipment, net	30,389,707	23,214,899
Intangible assets, net	15,788,258	17,063,580
Long term investments	177,529,881	44,175,993
Right-of-use assets	16,522,013
Other assets	265,359	144,148
TOTAL ASSETS	555,728,072	349,845,437
CURRENT LIABILITIES
Accounts payable	4,073,869	7,649,921
Accrued expenses	9,414,696	6,504,729
Accrued payroll and benefits	1,991,001	4,955,887
Lease liabilities	1,011,951
Deferred rent		173,952
Deferred revenue	26,274,362	77,769,629
Other current liabilities	17,262	16,561
TOTAL CURRENT LIABILITIES	42,783,141	97,070,679
LONG-TERM LIABILITIES
Lease liabilities, net of current portion	20,359,726
Deferred rent, net of current portion		3,703,364
Deferred revenue, net of current portion		5,035,142
TOTAL LONG-TERM LIABILITIES	20,359,726	8,738,506
Commitments and contingencies (Note 7)
Arrowhead Pharmaceuticals, Inc. stockholders' equity:
Common stock, $0.001 par value; 145,000,000 shares authorized; 102,250,872 and 95,506,271 shares issued and outstanding as of June 30, 2020 and September 30, 2019, respectively	194,620	187,876
Additional paid-in capital	948,532,470	664,086,155
Accumulated other comprehensive income (loss)	(175,219)	(391,624)
Accumulated deficit	(455,411,478)	(419,290,967)
Total Arrowhead Pharmaceuticals, Inc. stockholders' equity	493,140,393	244,591,440
Noncontrolling interest	(555,188)	(555,188)
TOTAL STOCKHOLDERS’ EQUITY	492,585,205	244,036,252
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 555,728,072	$ 349,845,437

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2020	Sep. 30, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	145,000,000	145,000,000
Common stock, shares issued	102,250,872	95,506,271
Common stock, shares outstanding	102,250,872	95,506,271

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) (unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
REVENUE	$ 27,375,778	$ 42,696,636	$ 80,359,211	$ 125,502,807
Type of Revenue [Extensible List]	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember
OPERATING EXPENSES
Research and development	$ 32,573,134	$ 19,291,710	$ 85,390,086	$ 57,662,381
General and administrative expenses	10,748,506	4,809,177	38,008,836	16,287,841
TOTAL OPERATING EXPENSES	43,321,640	24,100,887	123,398,922	73,950,222
OPERATING INCOME (LOSS)	(15,945,862)	18,595,749	(43,039,711)	51,552,585
OTHER INCOME (EXPENSE)
Interest income (expense), net	2,334,649	1,739,959	6,919,200	4,717,359
TOTAL OTHER INCOME (EXPENSE)	2,334,649	1,739,959	6,919,200	4,717,359
INCOME (LOSS) BEFORE INCOME TAXES	(13,611,213)	20,335,708	(36,120,511)	56,269,944
NET INCOME (LOSS)	$ (13,611,213)	$ 20,335,708	$ (36,120,511)	$ 56,269,944
NET INCOME (LOSS) PER SHARE - BASIC	$ (0.13)	$ 0.21	$ (0.36)	$ 0.60
NET INCOME (LOSS) PER SHARE - DILUTED	$ (0.13)	$ 0.21	$ (0.36)	$ 0.58
Weighted average shares outstanding - basic	101,843,436	94,935,471	100,184,216	93,364,102
Weighted average shares outstanding - diluted	101,843,436	98,884,744	100,184,216	97,814,019
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Foreign currency translation adjustments	$ 453,895	$ (31,172)	$ 216,405	$ (81,514)
COMPREHENSIVE INCOME (LOSS)	$ (13,157,318)	$ 20,304,536	$ (35,904,106)	$ 56,188,430

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity (unaudited) - USD ($)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Non-controlling Interest
Beginning Balance, Amount at Sep. 30, 2018	$ 95,241,001	$ 180,875	$ 582,902,694	$ (21,564)	$ (487,265,816)	$ (555,188)
Beginning Balance, Shares at Sep. 30, 2018		88,505,302
Stock-based compensation	7,276,875		7,276,875
Exercise of stock options, Amount	6,442,005	$ 1,244	6,440,761
Exercise of stock options, Shares		1,244,161
Common stock - restricted stock units vesting, Amount		$ 2,197	(2,197)
Common stock - restricted stock units vesting, Shares		2,197,305
Common stock - issued for cash, Amount	60,521,729	$ 3,261	60,518,468
Common stock - issued for cash, Shares		3,260,869
Foreign currency translation adjustments	(81,514)			(81,514)
Net income (loss)	56,269,944				56,269,944
Ending Balance, Amount at Jun. 30, 2019	225,670,040	$ 187,577	657,136,601	(103,078)	(430,995,872)	(555,188)
Ending Balance, Shares at Jun. 30, 2019		95,207,637
Beginning Balance, Amount at Mar. 31, 2019	200,640,237	$ 187,035	652,411,876	(71,906)	(451,331,580)	(555,188)
Beginning Balance, Shares at Mar. 31, 2019		94,665,718
Stock-based compensation	1,957,993		1,957,993
Exercise of stock options, Amount	2,767,274	$ 542	2,766,732
Exercise of stock options, Shares		541,919
Foreign currency translation adjustments	(31,172)			(31,172)
Net income (loss)	20,335,708				20,335,708
Ending Balance, Amount at Jun. 30, 2019	225,670,040	$ 187,577	657,136,601	(103,078)	(430,995,872)	(555,188)
Ending Balance, Shares at Jun. 30, 2019		95,207,637
Beginning Balance, Amount at Sep. 30, 2019	244,036,252	$ 187,876	664,086,155	(391,624)	(419,290,967)	(555,188)
Beginning Balance, Shares at Sep. 30, 2019		95,506,271
Stock-based compensation	27,509,663		27,509,663
Exercise of stock options, Amount	$ 6,464,422	$ 989	6,463,433
Exercise of stock options, Shares	989,197	989,197
Common stock - restricted stock units vesting, Amount		$ 1,155	(1,155)
Common stock - restricted stock units vesting, Shares		1,155,404
Common stock - issued for cash, Amount	$ 250,478,974	$ 4,600	250,474,374
Common stock - issued for cash, Shares		4,600,000
Foreign currency translation adjustments	216,405			216,405
Net income (loss)	(36,120,511)				(36,120,511)
Ending Balance, Amount at Jun. 30, 2020	492,585,205	$ 194,620	948,532,470	(175,219)	(455,411,478)	(555,188)
Ending Balance, Shares at Jun. 30, 2020		102,250,872
Beginning Balance, Amount at Mar. 31, 2020	493,563,470	$ 194,117	936,353,920	(629,114)	(441,800,265)	(555,188)
Beginning Balance, Shares at Mar. 31, 2020		101,748,107
Stock-based compensation	10,046,208		10,046,208
Exercise of stock options, Amount	2,132,845	$ 303	2,132,542
Exercise of stock options, Shares		302,765
Common stock - restricted stock units vesting, Amount		$ 200	(200)
Common stock - restricted stock units vesting, Shares		200,000
Foreign currency translation adjustments	453,895			453,895
Net income (loss)	(13,611,213)				(13,611,213)
Ending Balance, Amount at Jun. 30, 2020	$ 492,585,205	$ 194,620	$ 948,532,470	$ (175,219)	$ (455,411,478)	$ (555,188)
Ending Balance, Shares at Jun. 30, 2020		102,250,872

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (36,120,511)	$ 56,269,944
Stock-based compensation	27,509,663	7,276,875
Depreciation and amortization	4,167,873	3,356,769
Amortization/(accretion) of note premiums	652,747	682,243
Changes in operating assets and liabilities:
Accounts receivable	(21,031,203)	(1,716,736)
Prepaid expenses and other current assets	(863,287)	(2,393,230)
Deferred revenue	(56,530,409)	97,940,261
Accounts payable	(3,576,053)	1,824,146
Accrued expenses	(54,217)	(3,477,235)
Other	1,303,852	(538,020)
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	(84,541,545)	159,225,017
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(10,067,360)	(4,170,285)
Purchases of marketable securities	(193,964,290)	(90,266,001)
Proceeds from sale of marketable securities	29,148,287	29,861,219
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	(174,883,363)	(64,575,067)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on notes payable		(2,415,150)
Proceeds from the exercises of stock options	6,464,423	6,442,005
Proceeds from the issuance of common stock	250,478,974	60,521,729
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	256,943,397	64,548,584
NET INCREASE (DECREASE) IN CASH	(2,481,511)	159,198,534
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	221,804,128	30,133,213
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 219,322,617	189,331,747
Supplementary disclosures:
Interest paid		(27,437)
Income Taxes Paid		$ (2,400)

Organization and Significant Ac

Organization and Significant Accounting Policies	9 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Organization and Significant Accounting Policies	NOTE 1. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Nature of Business and Recent Developments Arrowhead Pharmaceuticals, Inc. develops medicines that treat intractable diseases by silencing the genes that cause them. Using a broad portfolio of RNA chemistries and efficient modes of delivery, Arrowhead therapies trigger the RNA interference mechanism to induce rapid, deep and durable knockdown of target genes. RNA interference, or RNAi, is a mechanism present in living cells that inhibits the expression of a specific gene, thereby affecting the production of a specific protein. Arrowhead’s RNAi-based therapeutics leverage this natural pathway of gene silencing. The Company's pipeline includes ARO-AAT for liver disease associated with alpha-1 antitrypsin deficiency (AATD), ARO-APOC3 for hypertriglyceridemia, ARO-ANG3 for dyslipidemia, ARO-HSD for liver disease, ARO-ENaC for cystic fibrosis, ARO-HIF2 for renal cell carcinoma, ARO-LUNG2 as a candidate to treat chronic obstructive pulmonary disorder (COPD) and ARO-COV for treatment for the current novel coronavirus that causes COVID-19 and other possible future pulmonary-borne pathogens. -JNJ1 is being developed for an undisclosed liver-expressed target under a collaboration agreement with Janssen Pharmaceuticals, Inc. (“Janssen”). ARO-HBV (JNJ-3989) for chronic hepatitis B virus was out-licensed to Janssen in October 2018. ARO-LPA (AMG 890) for cardiovascular disease was out-licensed to Amgen Inc. (“Amgen”) in 2016. Arrowhead operates a lab facility in Madison, Wisconsin, where the Company’s research and development activities, including the development of RNAi therapeutics, are based. The Company’s principal executive offices are located in Pasadena, California. In March 2020, the Company entered into a sublease for additional research and development facility space in San Diego, California as discussed further in Note 8 below. During fiscal year 2020, the Company has continued to develop its pipeline and partnered candidates. The Company has began dosing in an adaptive design phase 2/3 trial, called SEQUOIA, with the potential to serve as a pivotal registration study of ARO-AAT. The Company also began dosing in its ARO-AAT 2002 study, a pilot open-label, multi-dose Phase 2 study to assess changes in novel histological activity scale in response to ARO-AAT over time in patients with alpha-1 antitrypsin deficiency associated liver disease. In addition, the Company also dosed the first patients in AROHSD1001, a Phase 1/2 clinical study of ARO-HSD, the Company’s investigational RNA interference therapeutic being developed as a treatment for patients with alcohol related and nonalcohol related liver diseases, such as nonalcoholic steatohepatitis (NASH). The Company also presented new clinical data on its two cardiometabolic candidates, ARO-APOC3 and ARO-ANG3, in two late-breaking oral presentations at the American Heart Association Scientific Sessions 2019. In addition, the Company filed an investigational new drug (“IND”) application to begin a phase 1b study of ARO-HIF2 and filed a clinical trials application (“CTA”) to begin a phase 1 study of ARO-ENaC. The Company’s partnered candidates under its collaboration agreements with Janssen and Amgen also continue to progress. Janssen began dosing patients in a phase 2b triple combination study called REEF-1, designed to enroll up to 450 patients with chronic hepatitis B infection, and in connection with the start of this study Arrowhead earned a $25 million milestone payment under the License Agreement (“Janssen License Agreement”). Janssen has also nominated the first of 3 potential candidates under the Research Collaboration and Option Agreement (“Janssen Collaboration Agreement”), ARO-JNJ1, and the Company is currently performing discovery, optimization and preclinical research and development for this candidate. (the “Second Collaboration and License Agreement” or “AMG 890 (ARO-LPA) Agreement”), In July 2020, Amgen initiated a Phase 2 clinical study, which will result in a $20 million milestone payment to the Company. The revenue recognition for these collaboration agreements is discussed further in Note 2 below. The Company is actively monitoring the ongoing COVID-19 pandemic. The financial results for the three and nine months ended June 30, 2020 were not significantly impacted by COVID-19. The Company temporarily paused enrollment in its two ARO-AAT studies, SEQUOIA and the ARO-AAT 2002 study, but resumed the process of screening and enrolling patients during the three months ended June 30, 2020. During the pause in enrollment, patients already enrolled in these studies continued to be dosed per protocol and continued to come in for their follow up visits. Additional delays have occurred in the Company’s earlier stage programs, but we do not expect a material impact to any program’s anticipated timelines. Several of the Company’s other clinical candidates are in the start-up stage (ARO-HSD, ARO-HIF2 and ARO-ENaC), during which significant clinical costs will continue to be incurred. Additionally, the Company’s operations at its research and development facilities in Madison, Wisconsin and San Diego, California, and its corporate headquarters in Pasadena, California have continued to operate with limited impact, other than for enhanced safety measures, including work from home policies. However, the Company cannot predict the impact of the progression of COVID-19 will have on future financial results due to a variety of factors including the ability of the Company’s clinical sites to continue to enroll subjects, the ability of the Company’s suppliers to continue to operate, the continued good health and safety of the Company’s employees, and ultimately the length of the COVID-19 pandemic. Liquidity The Consolidated Financial Statements have been prepared in conformity with the accounting principles generally accepted in the United States of America, which contemplate the continuation of the Company as a going concern. Historically, the Company’s primary source of financing has been through the sale of its securities. Research and development activities have required significant capital investment since the Company’s inception. The Company expects its operations to continue to require cash investment to pursue its research and development goals, including clinical trials and related drug manufacturing. At June 30, 2020 the Company had $219.3 million in cash and cash equivalents (including $1.8 million in restricted cash), $67.7 million in short-term investments, and $177.5 million in long-term investments to fund operations. During the nine months ended June 30, 2020, the Company’s cash and investments balance increased by $161.7 million, which was primarily the result of the December 2019 securities offering that generated $250.5 million in net cash proceeds for the Company, as discussed further in Note 6 below. These cash inflows were partially offset by cash outflows primarily related to operating activities. Summary of Significant Accounting Policies There have been no changes to the significant accounting policies disclosed in the Company’s most recent Annual Report on Form 10-K, except as a result of the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Update (“ASU”) No. 2016-02, Leases (ASC 842), as discussed below. Leases — The Company determines whether a contract is, or contains, a lease at inception. The Company classifies each of its leases as operating or financing considering factors such as the length of the lease term, the present value of the lease payments, the nature of the asset being leased, and the potential for ownership of the asset to transfer during the lease term. Leases with terms greater than one-year are recognized on the Consolidated Balance Sheets as Right-of-use assets and Lease liabilities and are measured at the present value of the fixed payments due over the expected lease term less the present value of any incentives, rebates or abatements expected to be received from the lessor. Options to extend a lease are typically excluded from the expected lease term as the exercise of the option is typically not reasonably certain. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis an amount equal to the lease payments over a similar term and in a similar economic environment. The Company records expense to recognize fixed lease payments on a straight-line basis over the expected lease term. Costs determined to be variable and not based on an index or rate are not included in the measurement of the lease liability and are expensed as incurred. Recent Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-02, Leases (Topic ASC 842). Under ASC 842, lessees are required to recognize a right-of-use asset and a right-of-use lease liability for virtually all leases other than those that meet the definition of a short-term lease. For income statement purposes, a dual model was retained, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense while finance leases will result in a front-loaded expense pattern (similar to current capital leases). The Company adopted this standard effective October 1, 2019 and elected the package of three practical expedients that permits an entity to a) not reassess whether expired or existing contracts contain leases, b) not reassess lease classification for existing or expired leases, and c) not consider whether previously capitalized initial direct costs would be appropriate under the new standard. At June 30 2020, the Company has recorded right-of-use assets of $16.5 million and right-of-use liabilities of $ 21.4 million on its Consolidated Balance Sheets for its research and development facility lease s in Madison, Wisconsin and San Diego, C alifornia , as well as its corporate headquarters lease in Pasadena, California, as discussed further in Note 8 below. The adoption of this standard did not have a material impact on the Company’s Consolidated Statement of Comprehensive Income (Loss) and the Company’s Consolidated Statement of Cash Flows. In November 2018, the FASB issued ASU No. 2018-18 Collaborative Arrangements (Topic 808). This update provides clarification on the interaction between Revenue Recognition (Topic 606) and Collaborative Arrangements (Topic 808) including the alignment of unit of account guidance between the two topics. ASU 2018-18 becomes effective for the Company in the first quarter of fiscal 2021 with early adoption permitted. The Company does not expect the adoption of this update to have a material effect on its Consolidated Financial Statements.

Collaboration and License Agree

Collaboration and License Agreements	9 Months Ended
	Jun. 30, 2020
Collaboration And License Agreements [Abstract]
Collaboration and License Agreements	NOTE 2. COLLABORATION AND LICENSE AGREEMENTS Amgen Inc. On September 28, 2016, the Company entered into two Collaboration and License agreements, and a Common Stock Purchase Agreement with Amgen Inc., a Delaware corporation (“Amgen”). Under one of the license agreements (the “Second Collaboration and License Agreement” or “AMG 890 (ARO-LPA) Agreement”), Amgen has received a worldwide, exclusive license to Arrowhead’s novel, RNAi ARO-LPA program. These RNAi molecules are designed to reduce elevated lipoprotein(a), which is a genetically validated, independent risk factor for atherosclerotic cardiovascular disease. Under the other license agreement (the “First Collaboration and License Agreement” or “ARO-AMG1 Agreement”), Amgen received an option to a worldwide, exclusive license for ARO-AMG1, an RNAi therapy for an undisclosed genetically validated cardiovascular target. In both agreements, Amgen is wholly responsible for clinical development and commercialization. Under the terms of the agreements taken together, the Company has received $35 million in upfront payments, $21.5 million in the form of an equity investment by Amgen in the Company’s Common Stock, and a $10 million milestone payment, and may receive up to $420 million in development, regulatory and sales milestone payments. The Company is further eligible to receive up to low double-digit royalties for sales of products under the AMG 890 (ARO-LPA) Agreement. In July 2019, Amgen informed the Company that it would not be exercising its option for an exclusive license for ARO-AMG1, and as such, there will be no further milestone or royalty payments under the ARO-AMG1 Agreement. The Company substantially completed its performance obligations under the AMG 890 (ARO-LPA) Agreement and the ARO-AMG1 Agreement. Future milestones and royalties achieved will be recognized in their entirety when earned. In July 2020, Amgen initiated a Phase 2 clinical study, which will result in a $20 million milestone payment to the Company. During the three months ended June 30, 2020 and 2019, the Company recognized $20.0 million and $0 million of Revenue associated with its agreements with Amgen, respectively. During the nine months ended June 30, 2020 and 2019, the Company recognized $20.0 million and $0.3 million of Revenue associated with its agreements with Amgen, respectively. As of June 30, 2020, there were $20.0 million in contract assets recorded as accounts receivable, and $0 contract liabilities recorded as current deferred revenue on the Company’s Consolidated Balance Sheets. Janssen Pharmaceuticals, Inc. On October 3, 2018, the Company entered into a License Agreement (“Janssen License Agreement”) and a Research Collaboration and Option Agreement (“Janssen Collaboration Agreement”) with Janssen Pharmaceuticals, Inc. (“Janssen”) part of the Janssen Pharmaceutical Companies of Johnson & Johnson. The Company also entered into a Stock Purchase Agreement (“JJDC Stock Purchase Agreement”) with Johnson & Johnson Innovation-JJDC, Inc. (“JJDC”), a New Jersey corporation. Under the Janssen License Agreement, Janssen has received a worldwide, exclusive license to the Company’s JNJ-3989 (ARO-HBV) program, the Company’s third-generation subcutaneously administered RNAi therapeutic candidate being developed as a potentially curative therapy for patients with chronic hepatitis B virus infection. Beyond the Company’s ongoing Phase 1/2 study of JNJ-3989 (ARO-HBV), Janssen will be wholly responsible for clinical development and commercialization. Under the Janssen Collaboration Agreement, Janssen will be able to select three new targets against which Arrowhead will develop clinical candidates. These candidates are subject to certain restrictions and will not include candidates in the Company’s current pipeline. The Company will perform discovery, optimization and preclinical research and development, entirely funded by Janssen, sufficient to allow the filing of a U.S. Investigational New Drug application or equivalent, at which time Janssen will have the option to take an exclusive license. If the option is exercised, Janssen will be wholly responsible for clinical development and commercialization of each optioned candidate. Under the terms of the agreements taken together, the Company has received $175 million as an upfront payment, $75 million in the form of an equity investment by JJDC in Arrowhead common stock under the JJDC The Company has evaluated these agreements in accordance with the new revenue recognition standard that became effective for the Company on October 1, 2018. The adoption of the new revenue standard did not have a material impact on the balances reported when evaluated under the superseded revenue standard. At the inception of these agreements, the Company has identified one distinct performance obligation. Regarding the Janssen License Agreement, the Company determined that the key deliverables included the license and certain R&D services including the Company’s responsibility to complete the ongoing Phase 1/2 study of JNJ-3989 (ARO-HBV) and the Company’s responsibility to ensure certain manufacturing of JNJ-3989 (ARO-HBV) drug product is completed and delivered to Janssen (the “Janssen R&D Services”). Due to the specialized and unique nature of these Janssen R&D services, and their direct relationship with the license, the Company determined that these deliverables represent one distinct bundle and thus, one performance obligation. The Company also determined that Janssen’s option to require the Company to develop up to three new targets is not a material right, and thus, not a performance obligation at the onset of the agreement. The consideration for this option will be accounted for if and when it is exercised. The Company determined the transaction price totaled approximately $252.6 million which includes the upfront payment, the premium paid by JJDC for its equity investment in the Company, the two $25 million milestone payments earned and estimated payments for reimbursable Janssen R&D services to be performed. The Company has allocated the total $252.6 million initial transaction price to its one distinct performance obligation for the JNJ-3989 (ARO-HBV) license and the associated Janssen R&D Services. This revenue will be recognized using a proportional performance method (based on actual labor hours versus estimated total labor hours) beginning in October 2018 and ending as the Company’s efforts in overseeing the ongoing phase 1/2 clinical trial are completed. During the three months ended June 30, 2020 and 2019, the Company recognized approximately $6.9 million and $42.3 million of Revenue associated with its agreements with Janssen and JJDC, respectively. Janssen has also selected the first of the three targets under the Janssen Collaboration Agreement, now referred to as ARO-JNJ1, and the Company has begun to conduct its discovery, optimization and preclinical research and development of ARO-JNJ1. All costs and labor hours spent by the Company will be entirely funded by Janssen. During the three months ended June 30, 2020 and 2019, the Company recognized approximately $0.4 million and $0.4 million of Revenue associated with its efforts on the ARO-JNJ1 candidate, respectively. During the nine months ended June 30, 2020 and 2019, the Company recognized $2.4 million and $0.4 million of Revenue associated with these efforts on the ARO-JNJ1 candidate, respectively. As of June 30, 2020, there were $1.7 million of cont ract assets recorded as accounts t deferred revenue on the Company’s Consolidated Balance

Property and Equipment

Property and Equipment	9 Months Ended
	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Property and Equipment	NOTE 3. PROPERTY AND EQUIPMENT The following table summarizes the Company’s major classes of property and equipment: June 30, 2020 September 30, 2019 Computers, office equipment and furniture $ 661,927 $ 637,577 Research equipment 19,514,871 12,932,304 Software 293,189 147,254 Leasehold improvements 24,883,656 21,579,415 Total gross fixed assets 45,353,643 35,296,550 Less: Accumulated depreciation and amortization (14,963,936 ) (12,081,651 ) Property and equipment, net $ 30,389,707 $ 23,214,899 Depreciation and amortization expense for property and equipment for the three months ended June 30, 2020 and 2019 was $1,111,293 and $578,342, respectively. Depreciation and amortization expense for property and equipment for the nine months ended June 30, 2020 and 2019 was $2,892,551 and $2,081,447, respectively.

Investments

Investments	9 Months Ended
	Jun. 30, 2020
Held To Maturity Securities Classified [Abstract]
Investments	NOTE 4. INVESTMENTS The Company invests a portion of its excess cash balances in short-term and long-term debt securities. Investments at June 30, 2020 consisted of corporate bonds with maturities remaining of less than 36 months. The Company may also invest excess cash balances in certificates of deposits, money market accounts, government-sponsored enterprise securities, corporate bonds and/or commercial paper. The Company accounts for its investments in accordance with FASB ASC 320, Investments – Debt and Equity Securities. At June 30, 2020, all investments were classified as held-to-maturity securities. The following tables summarize the Company’s short-term and long-term investments as of June 30, 2020 and September 30, 2019. As of June 30, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial notes (due within one year) $ 67,709,263 $ 1,188,416 $ — $ 68,897,679 Commercial notes (due within one through three years) $ 177,529,881 $ 5,845,177 $ (14,833) $ 183,360,225 Total $ 245,239,144 $ 7,033,593 $ (14,833) $ 252,257,904 ‬ As of September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial notes (due within one year) $ 36,899,894 $ 222,584 $ — $ 37,122,478 Commercial notes (due within one through three years) $ 44,175,993 $ 875,258 $ — $ 45,051,251 Total $ 81,075,887 $ 1,097,842 $ — $ 82,173,729

Intangible Assets

Intangible Assets	9 Months Ended
	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	NOTE 5. INTANGIBLE ASSETS Intangible assets subject to amortization include patents and a license agreement capitalized as part of the Novartis RNAi asset acquisition in March 2015. The license agreement associated with the Novartis RNAi asset acquisition is being amortized over the estimated life remaining at the time of acquisition, which was 21 years, and the accumulated amortization of the asset is $791,495. The patents associated with the Novartis RNAi asset acquisition are being amortized over the estimated life remaining at the time of acquisition, which was 14 years, and the accumulated amortization of the assets is $8,277,460. Amortization expense for the three months ended June 30, 2020 and 2019 was $425,107 and $425,107, respectively. Amortization expense for the nine months ended June 30, 2020 and 2019 was $1,275,322 and $1,275,322, respectively. Amortization expense is expected to be $425,107 for the remainder of fiscal 2020, $1,700,429 in 2021, $1,700,429 in 2022, $1,700,429 in 2023, $1,700,429 in 2024, and $8,561,435 thereafter. The following table provides details on the Company’s intangible asset balances: Intangible assets subject to amortization Balance at September 30, 2019 $ 17,063,580 Impairment — Amortization (1,275,322 ) Balance at June 30, 2020 $ 15,788,258

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Stockholders' Equity	NOTE 6. STOCKHOLDERS’ EQUITY At June 30, 2020, the Company had a total of 150,000,000 shares of capital stock authorized for issuance, consisting of 145,000,000 shares of Common Stock, par value $0.001 per share, and 5,000,000 shares of Preferred Stock, par value $0.001 per share. At June 30, 2020, 102,250,872 In December 2019, the Company sold 4,600,000 shares of its Common Stock in a public offering at a price of $58.00 per share. The aggregate purchase price paid by the investors for the Common Stock was $266.8 million, and the Company received net proceeds of $250.5 million after deducting advisory fees and offering expenses. Effective August 5, 2020, the Company entered into an Open Market Sale Agreement (the “ATM Agreement”), pursuant to which the Company may, from time to time, sell up to $250,000,000 in shares of the Company’s common stock through Jefferies LLC, acting as the sales agent and/or principal, in an at-the-market offering (“ATM Offering”). The Company is not required to sell shares under the ATM Agreement. The Company will pay Jefferies LLC a commission of up to 3.0% of the aggregate gross proceeds received from all sales of the common stock under the ATM Agreement. Unless otherwise terminated, the ATM Agreement continues until the earlier of selling all shares available under the ATM Agreement or December 2, 2022. No sales have been made under the ATM Agreement.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 7. COMMITMENTS AND CONTINGENCIES Litigation On occasion, the Company may be subject to various claims and legal proceedings in the ordinary course of business. If the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount is reasonably estimable, the Company will accrue a liability for the estimated loss. There were no contingent liabilities recorded as of June 30, 2020. Purchase Commitments In the normal course of business, the Company enters into various purchase commitments for the manufacture of drug components, for toxicology studies, and for clinical studies. As of June 30, 2020, these future commitments were estimated at approximately $83.0 million, of which approximately $20.5 million is expected to be incurred in fiscal 2020, and $62.5 million is expected to be incurred beyond fiscal 2020. Technology License Commitments The Company has licensed from third parties the rights to use certain technologies for its research and development activities, as well as in any products the Company may develop using these licensed technologies. These agreements and other similar agreements often require milestone and royalty payments. Milestone payments, for example, may be required as the research and development process progresses through various stages of development, such as when clinical candidates enter or progress through clinical trials, upon NDA and upon certain sales level milestones. These milestone payments could amount to the mid to upper double-digit millions of dollars. During the three months ended June 30, 2020, the Company did not accrue any milestone payment. During the nine months ended June 30, 2020, the Company accrued a $0.9 million milestone payment related to the progression of the ARO-ENaC program. During the three and nine months ended June 30, 2019, the Company did not accrue for any milestone payments. In certain agreements, the Company may be required to make mid to high single-digit percentage royalty payments based on a percentage of the sales of the relevant products.

Leases

Leases	9 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	NOTE 8. LEASES Leases In April 2019, the Company entered into a lease for its corporate headquarters in Pasadena, California. The 91 month office building lease between the Company and 177 Colorado Owner, LLC is for approximately 24,000 square feet of office space located at 177 E. Colorado Blvd, Pasadena, California. The increased capacity of this new office space compared to the Company’s prior corporate headquarters will accommodate increased personnel as the Company’s pipeline of drug candidates expands and moves closer to market. Lease payments began on September 30, 2019 and are estimated to total approximately $8.7 million over the term. In January 2016, the Company entered into a lease for its research facility in Madison, Wisconsin. The lease was for approximately 60,000 square feet of office and laboratory space and had an expiration date of September 30, 2026. The lease was amended in January 2019 to expand the rentable square feet by an additional 14,000 square feet and to extend the lease expiration date to September 2029. In May 2020, the Company further amended the lease to increase the rentable square feet by an additional 26,000 square feet and extended the lease expiration date to September 30, 2031. Lease payments are estimated to total approximately $26.2 million for the term. The lease contains two options to renew for two terms of five years. The exercise of these options were not determined to be reasonably certain and thus was not included in lease liabilities on the Company’s Consolidated Balance Sheet at June 30, 2020. In March 2020, the Company entered into a sublease agreement (the “Sublease”) with Halozyme, Inc. for additional research and development facility space in San Diego, California. The Sublease provides additional space needed to accommodate the recent growth of the Company’s personnel and discovery efforts. The lease is for approximately 21,000 Operating lease cost during the three and nine months ended June 30, 2020 was $0.8 million and $1.7 million, respectively. Variable lease costs during the three and nine months ended June 30, 2020 were $0.2 million and $0.6 million, respectively. There was no short-term lease cost during the three and nine months ended June 30, 2020. The following table presents maturities of operating lease liabilities on an undiscounted basis as of June 30, 2020: 2020 (remainder of fiscal year) $ 681,214 2021 3,091,900 2022 3,853,290 2023 3,406,754 2024 3,269,674 2025 and thereafter 18,689,588 Total lease payments 32,992,420 Less imputed interest (11,620,743) Total operating lease liabilities (includes current portion) $ 21,371,677 Cash paid for the amounts included in the measurement of the operating lease liabilities on the Company’s Consolidated Balance Sheet and included in Other changes in operating assets and liabilities within cash flows from operating activities on the Company’s Consolidated Statement of Cash Flow for the three and nine months ended June 30, 2020 was $0.5 million and $1.1 million, respectively. The weighted-average remaining lease term and weighted-average discount rate for all leases as of June 30, 2020 was 9.6 years and 8.4%, respectively. As of September 30, 2019, future minimum lease payments due in fiscal years under operating leases were as follows: 2020 $ 1,521,451 2021 2,256,379 2022 2,521,446 2023 2,590,558 2024 2,661,512 2025 and thereafter 10,834,206 Total $ 22,385,552

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	NOTE 9 . STOCK-BASED COMPENSATION Arrowhead has two plans that provide for equity-based compensation. Under the 2004 Equity Incentive Plan and 2013 Incentive Plan, as of June 30, 2020, 744,250 and 5,652,008 shares, respectively, of Arrowhead’s Common Stock are reserved for the grant of stock options, stock appreciation rights, restricted stock awards and performance unit/share awards to employees, consultants and others. No further grants may be made under the 2004 Equity Incentive Plan. As of June 30, 2020, there were options granted and outstanding to purchase 744,250 and 2,672,851 shares of Common Stock under the 2004 Equity Incentive Plan and the 2013 Incentive Plan, respectively, and there were 2,583,000 restricted stock units granted and outstanding under the 2013 Incentive Plan. Also, as of June 30, 2020, there were 1,112,463 shares reserved for options and 744,075 shares reserved for restricted stock units issued as inducement grants to new employees outside of equity compensation plans. During the three months ended June 30, 2020, 0 options and 0 restricted stock units were granted under the 2013 Incentive Plan, and 134,000 options and 153,000 restricted stock units were granted as inducement awards to new employees outside of equity incentive plans. During the nine months ended June 30, 2020, 310,500 options and 1,749,071 restricted stock units were granted under the 2013 Incentive Plan, and 477,000 options and 737,575 restricted stock units were granted as inducement awards to new employees outside of the equity incentive plans. The following table summarizes information about stock options: Number of Options Outstanding Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Balance At September 30, 2019 4,773,670 $ 8.16 Granted 787,500 50.42 Cancelled (42,409 ) 25.04 Exercised (989,197 ) 6.54 Balance At June 30, 2020 4,529,564 $ 15.71 6.2 years $ 133,654,814 Exercisable At June 30, 2020 2,928,765 $ 7.66 4.8 years $ 104,700,213 Stock-based compensation expense related to stock options for the three months ended June 30, 2020 and 2019 was $2,659,265 and $1,016,206, respectively. Stock-based compensation expense related to stock options for the nine months ended June 30, 2020 and 2019 was $6,796,175 and $2,823,706, respectively. For non-qualified stock options, the expense creates a timing difference, resulting in a deferred tax asset, which is fully reserved by a valuation allowance. The grant date fair value of the options granted by the Company for the three months ended June 30, 2020 and 2019 was $3,421,181 and $1,316,220, respectively. The grant date fair value of the options granted by the Company for the nine months ended June 30, 2020 and 2019 was $30,020,524 and $9,453,469, respectively. The intrinsic value of the options exercised during the three months ended June 30, 2020 and 2019 was $9,529,237 and $9,349,226, respectively. The intrinsic value of the options exercised during the nine months ended June 30, 2020 and 2019 was $39,775,062 and $17,471,520, respectively. As of June 30, 2020, the pre-tax compensation expense for all outstanding unvested stock options in the amount of $35,021,715 will be recognized in the Company’s results of operations over a weighted average period of 3.3 The fair value of each stock option award is estimated on the date of grant using the Black-Scholes option pricing model. The Black-Scholes option valuation model was developed for use in estimating the fair value of traded options, which do not have vesting restrictions and are fully transferable. The determination of the fair value of each stock option is affected by the Company’s stock price on the date of grant, as well as assumptions regarding a number of highly complex and subjective variables. Because the Company’s employee stock options have characteristics significantly different from those of traded options, and because changes in the subjective input assumptions can materially affect the fair value estimate, in management’s opinion, the existing models do not necessarily provide a reliable single measure of the fair value of its employee stock options. The assumptions used to value stock options are as follows: Nine Months Ended June 30, 2020 2019 Dividend yield — — Risk-free interest rate 0.4 – 1.8% 1.9 – 3.1% Volatility 90.5 – 91.9% 115% Expected life (in years) 6.25 6.25 Weighted average grant date fair value per share of options granted $38.12 $12.21 The dividend yield is zero as the Company currently does not pay a dividend. The risk-free interest rate is based on that of the U.S. Treasury bond. Volatility is estimated based on volatility average of the Company’s Common Stock price. Restricted Stock Units Restricted stock units (RSUs), including time-based and performance-based awards, were granted under the Company’s 2013 Incentive Plan and as inducements grants granted outside of the Plan. During the three months ended June 30, 2020, the Company issued 0 RSUs under the 2013 Incentive Plan and 153,000 RSUs as inducement awards. During the nine months ended June 30, 2020, the Company issued 1,749,071 RSUs under the 2013 Incentive Plan and 737,575 RSUs as inducement awards. At vesting, each outstanding RSU will be exchanged for one share of the Company’s Common Stock. RSU recipients may elect to net share settle upon vesting, in which case the Company pays the employee’s income taxes due upon vesting and withholds a number of shares of Common Stock of equal value. RSU awards generally vest subject to the satisfaction of service requirements or the satisfaction of both service requirements and achievement of certain performance targets. The following table summarizes the activity of the Company’s RSUs: Number of RSUs Weighted- Average Grant Date Fair Value Unvested at September 30, 2019 2,062,833 $ 9.43 Granted 2,486,646 57.04 Vested (1,155,404 ) 9.65 Forfeited (67,000 ) 31.78 Unvested at June 30, 2020 3,327,075 $ 44.49 During the three months ended June 30, 2020 and 2019, the Company recorded $7,386,943 and $941,788 of expense related to RSUs, respectively. During the nine months ended June 30, 2020 and 2019, the Company recorded $20,713,488 and $4,453,169 of expense related to RSUs, respectively. Such expense is included in stock-based compensation expense in the Company’s Consolidated Statement of Operations and Comprehensive Income (Loss). For RSUs, the expense creates a timing difference, resulting in a deferred tax asset, which is fully reserved by a valuation allowance. For RSUs, the grant date fair value of the award is based on the Company’s closing stock price at the grant date, with consideration given to the probability of achieving performance conditions for performance-based awards. As of June 30, 2020 the pre-tax compensation expense for all unvested RSUs in the amount of $87,634,315 will be recognized in the Company’s results of operations over a weighted average period of 3.3 years.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 10 . FAIR VALUE MEASUREMENTS The Company measures its financial assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e., exit price) in an orderly transaction between market participants at the measurement date. Additionally, the Company is required to provide disclosure and categorize assets and liabilities measured at fair value into one of three different levels depending on the assumptions (i.e., inputs) used in the valuation. Level 1 provides the most reliable measure of fair value while Level 3 generally requires significant management judgment. Financial assets and liabilities are classified in their entirety based on the lowest level of input significant to the fair value measurement. The fair value hierarchy is defined as follows: Level 1—Valuations are based on unadjusted quoted prices in active markets for identical assets or liabilities. Level 2—Valuations are based on quoted prices for similar assets or liabilities in active markets, or quoted prices in markets that are not active for which significant inputs are observable, either directly or indirectly. Level 3—Valuations are based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. Inputs reflect management’s best estimate of what market participants would use in valuing the asset or liability at the measurement date. The following table summarizes fair value measurements at June 30, 2020 and September 30, 2019 for assets and liabilities measured at fair value on a recurring basis: June 30, 2020: Level 1 Level 2 Level 3 Total Cash and cash equivalents $ 219,322,617 $ — $ — $ 219,322,617 Short-term investments $ 68,897,679 $ — $ — $ 68,897,679 Long-term investments $ 183,360,225 $ — $ — $ 183,360,225 Contingent consideration $ — $ — $ — $ — September 30, 2019 Level 1 Level 2 Level 3 Total Cash and cash equivalents $ 221,804,128 $ — $ — $ 221,804,128 Short-term investments $ 37,122,478 $ — $ — $ 37,122,478 Long-term investments $ 45,051,251 $ — $ — $ 45,051,251 Contingent consideration $ — $ — $ — $ — The Company had a liability for contingent consideration related to its acquisition of the Roche RNAi business completed in 2011. The fair value measurement of the contingent consideration obligations is determined using Level 3 inputs. The fair value of contingent consideration obligations is based on a discounted cash flow model using a probability-weighted income approach. The measurement is based upon unobservable inputs supported by little or no market activity based on the Company’s assumptions and experience. Estimating timing to complete the development and obtain approval of products is difficult, and there are inherent uncertainties in developing a product candidate, such as obtaining FDA and other regulatory approvals. In determining the probability of regulatory approval and commercial success, the Company utilizes data regarding similar milestone events from several sources, including industry studies and its own experience. These fair value measurements represent Level 3 measurements as they are based on significant inputs not observable in the market. Significant judgment is employed in determining the appropriateness of these assumptions as of the acquisition date and for each subsequent period. Accordingly, changes in assumptions could have a material impact on the amount of contingent consideration expense the Company records in any given period. In November 2016, the Company announced the discontinuation of its clinical trial efforts for ARC-520, ARC-AAT and ARC-521. Given this development, the Company assessed the fair value of its contingent consideration obligation to be $0 at June 30, 2020 and September 30, 2019.

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	9 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Leases	Leases — The Company determines whether a contract is, or contains, a lease at inception. The Company classifies each of its leases as operating or financing considering factors such as the length of the lease term, the present value of the lease payments, the nature of the asset being leased, and the potential for ownership of the asset to transfer during the lease term. Leases with terms greater than one-year are recognized on the Consolidated Balance Sheets as Right-of-use assets and Lease liabilities and are measured at the present value of the fixed payments due over the expected lease term less the present value of any incentives, rebates or abatements expected to be received from the lessor. Options to extend a lease are typically excluded from the expected lease term as the exercise of the option is typically not reasonably certain. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis an amount equal to the lease payments over a similar term and in a similar economic environment. The Company records expense to recognize fixed lease payments on a straight-line basis over the expected lease term. Costs determined to be variable and not based on an index or rate are not included in the measurement of the lease liability and are expensed as incurred.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-02, Leases (Topic ASC 842). Under ASC 842, lessees are required to recognize a right-of-use asset and a right-of-use lease liability for virtually all leases other than those that meet the definition of a short-term lease. For income statement purposes, a dual model was retained, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense while finance leases will result in a front-loaded expense pattern (similar to current capital leases). The Company adopted this standard effective October 1, 2019 and elected the package of three practical expedients that permits an entity to a) not reassess whether expired or existing contracts contain leases, b) not reassess lease classification for existing or expired leases, and c) not consider whether previously capitalized initial direct costs would be appropriate under the new standard. At June 30 2020, the Company has recorded right-of-use assets of $16.5 million and right-of-use liabilities of $ 21.4 million on its Consolidated Balance Sheets for its research and development facility lease s in Madison, Wisconsin and San Diego, C alifornia , as well as its corporate headquarters lease in Pasadena, California, as discussed further in Note 8 below. The adoption of this standard did not have a material impact on the Company’s Consolidated Statement of Comprehensive Income (Loss) and the Company’s Consolidated Statement of Cash Flows. In November 2018, the FASB issued ASU No. 2018-18 Collaborative Arrangements (Topic 808). This update provides clarification on the interaction between Revenue Recognition (Topic 606) and Collaborative Arrangements (Topic 808) including the alignment of unit of account guidance between the two topics. ASU 2018-18 becomes effective for the Company in the first quarter of fiscal 2021 with early adoption permitted. The Company does not expect the adoption of this update to have a material effect on its Consolidated Financial Statements.

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Summary of Property and Equipment	The following table summarizes the Company’s major classes of property and equipment: June 30, 2020 September 30, 2019 Computers, office equipment and furniture $ 661,927 $ 637,577 Research equipment 19,514,871 12,932,304 Software 293,189 147,254 Leasehold improvements 24,883,656 21,579,415 Total gross fixed assets 45,353,643 35,296,550 Less: Accumulated depreciation and amortization (14,963,936 ) (12,081,651 ) Property and equipment, net $ 30,389,707 $ 23,214,899

Investments (Tables)

Investments (Tables)	9 Months Ended
	Jun. 30, 2020
Held To Maturity Securities Classified [Abstract]
Summary of Short-term and Long-term Investments	The following tables summarize the Company’s short-term and long-term investments as of June 30, 2020 and September 30, 2019. As of June 30, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial notes (due within one year) $ 67,709,263 $ 1,188,416 $ — $ 68,897,679 Commercial notes (due within one through three years) $ 177,529,881 $ 5,845,177 $ (14,833) $ 183,360,225 Total $ 245,239,144 $ 7,033,593 $ (14,833) $ 252,257,904 ‬ As of September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial notes (due within one year) $ 36,899,894 $ 222,584 $ — $ 37,122,478 Commercial notes (due within one through three years) $ 44,175,993 $ 875,258 $ — $ 45,051,251 Total $ 81,075,887 $ 1,097,842 $ — $ 82,173,729

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	The following table provides details on the Company’s intangible asset balances: Intangible assets subject to amortization Balance at September 30, 2019 $ 17,063,580 Impairment — Amortization (1,275,322 ) Balance at June 30, 2020 $ 15,788,258

Leases (Tables)

Leases (Tables)	9 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Summary of Maturities of Operating Lease Liabilities on an Undiscounted Basis	The following table presents maturities of operating lease liabilities on an undiscounted basis as of June 30, 2020: 2020 (remainder of fiscal year) $ 681,214 2021 3,091,900 2022 3,853,290 2023 3,406,754 2024 3,269,674 2025 and thereafter 18,689,588 Total lease payments 32,992,420 Less imputed interest (11,620,743) Total operating lease liabilities (includes current portion) $ 21,371,677
Future Minimum Lease Payments Under Operating Leases	As of September 30, 2019, future minimum lease payments due in fiscal years under operating leases were as follows: 2020 $ 1,521,451 2021 2,256,379 2022 2,521,446 2023 2,590,558 2024 2,661,512 2025 and thereafter 10,834,206 Total $ 22,385,552

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summarized Information about Stock Options	The following table summarizes information about stock options: Number of Options Outstanding Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Balance At September 30, 2019 4,773,670 $ 8.16 Granted 787,500 50.42 Cancelled (42,409 ) 25.04 Exercised (989,197 ) 6.54 Balance At June 30, 2020 4,529,564 $ 15.71 6.2 years $ 133,654,814 Exercisable At June 30, 2020 2,928,765 $ 7.66 4.8 years $ 104,700,213
Assumptions Used to Value Stock Options	The assumptions used to value stock options are as follows: Nine Months Ended June 30, 2020 2019 Dividend yield — — Risk-free interest rate 0.4 – 1.8% 1.9 – 3.1% Volatility 90.5 – 91.9% 115% Expected life (in years) 6.25 6.25 Weighted average grant date fair value per share of options granted $38.12 $12.21
Summary of Share Activity Related to RSUs	The following table summarizes the activity of the Company’s RSUs: Number of RSUs Weighted- Average Grant Date Fair Value Unvested at September 30, 2019 2,062,833 $ 9.43 Granted 2,486,646 57.04 Vested (1,155,404 ) 9.65 Forfeited (67,000 ) 31.78 Unvested at June 30, 2020 3,327,075 $ 44.49

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements for Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes fair value measurements at June 30, 2020 and September 30, 2019 for assets and liabilities measured at fair value on a recurring basis: June 30, 2020: Level 1 Level 2 Level 3 Total Cash and cash equivalents $ 219,322,617 $ — $ — $ 219,322,617 Short-term investments $ 68,897,679 $ — $ — $ 68,897,679 Long-term investments $ 183,360,225 $ — $ — $ 183,360,225 Contingent consideration $ — $ — $ — $ — September 30, 2019 Level 1 Level 2 Level 3 Total Cash and cash equivalents $ 221,804,128 $ — $ — $ 221,804,128 Short-term investments $ 37,122,478 $ — $ — $ 37,122,478 Long-term investments $ 45,051,251 $ — $ — $ 45,051,251 Contingent consideration $ — $ — $ — $ —

Organization and Significant _3

Organization and Significant Accounting Policies - Additional Information (Detail)	Oct. 03, 2018USD ($)Target	Sep. 28, 2016USD ($)	Dec. 31, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jul. 31, 2020USD ($)	Sep. 30, 2019USD ($)
Organization And Significant Accounting Policies [Line Items]
Proceeds from the issuance of common stock			$ 250,500,000	$ 250,478,974	$ 60,521,729
Cash and cash equivalents				219,322,617			$ 221,804,128
Restricted Cash				1,800,000
Short term investments				67,709,263			36,899,894
Long term investments				177,529,881			$ 44,175,993
Net increase (decrease) in cash and investments				161,700,000
Right-of-use assets				16,522,013
Right-of-use liabilities				21,371,677
Janssen | JNJ-3989 (ARO-HBV) Agreement
Organization And Significant Accounting Policies [Line Items]
Milestone payment	$ 25,000,000			25,000,000
Janssen | Collaboration Agreement
Organization And Significant Accounting Policies [Line Items]
Number of additional targets for development and sales milestone payments | Target	3
Janssen and JJDC | Collaboration and License agreements
Organization And Significant Accounting Policies [Line Items]
Cash received as due under agreement	$ 175,000,000
JJDC | Common Stock Purchase Agreement
Organization And Significant Accounting Policies [Line Items]
Proceeds from the issuance of common stock	75,000,000
Amgen | License Collaboration and Stock Purchase Agreement
Organization And Significant Accounting Policies [Line Items]
Cash received as due under agreement		$ 35,000,000
Proceeds from the issuance of common stock		21,500,000
Amgen | AMG-890 (ARO-LPA) Agreement
Organization And Significant Accounting Policies [Line Items]
Milestone payment		$ 10,000,000
Maximum | Janssen | License Agreement
Organization And Significant Accounting Policies [Line Items]
Development regulatory and sales milestones payments	1,600,000,000
Maximum | Janssen | Collaboration Agreement
Organization And Significant Accounting Policies [Line Items]
Development regulatory and sales milestones payments	$ 1,900,000,000
Maximum | Amgen | AMG-890 (ARO-LPA) Agreement
Organization And Significant Accounting Policies [Line Items]
Development regulatory and sales milestones payments				$ 420,000,000
Subsequent Event | Amgen
Organization And Significant Accounting Policies [Line Items]
Milestone payment						$ 20,000,000

Collaboration and License Agr_2

Collaboration and License Agreements - Amgen, Inc - Additional Information (Detail)	Sep. 28, 2016USD ($)Agreement	Dec. 31, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jul. 31, 2020USD ($)	Sep. 30, 2019USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from the issuance of common stock		$ 250,500,000			$ 250,478,974	$ 60,521,729
Revenues			$ 27,375,778	$ 42,696,636	$ 80,359,211	$ 125,502,807
Type of Revenue [Extensible List]			arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember	arwr:TechnologyLicensesCollaborativeResearchAndDevelopmentArrangementsResearchGrantsAndProductSalesMember
Contract liabilities			$ 26,274,362		$ 26,274,362			$ 77,769,629
Amgen | Subsequent Event
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment							$ 20,000,000
Collaboration and License agreements | Amgen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement date	Sep. 28, 2016
Number of agreements | Agreement	2
Cash received as due under collaboration agreement	$ 35,000,000
AMG-890 (ARO-LPA) Agreement | Amgen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment	10,000,000
AMG-890 (ARO-LPA) Agreement | Amgen | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development regulatory and sales milestones payments			420,000,000		420,000,000
License Collaboration and Stock Purchase Agreement | Amgen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from the issuance of common stock	$ 21,500,000
AMG 890 (ARO-LPA) and ARO-AMG1 Agreement | Amgen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues			$ 20,000,000	$ 0	$ 20,000,000	$ 300,000
Type of Revenue [Extensible List]			us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Contract liabilities			$ 0		$ 0
Contract assets			$ 20,000,000		$ 20,000,000
AMG 890 (ARO-LPA) and ARO-AMG1 Agreement | Amgen | Subsequent Event
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment							$ 20,000,000

Collaboration and License Agr_3

Collaboration and License Agreements - Janssen Pharmaceuticals, Inc - Additional Information (Detail)	Oct. 03, 2018USD ($)TargetObligation	Dec. 31, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from the issuance of common stock		$ 250,500,000			$ 250,478,974	$ 60,521,729
Revenues			$ 27,375,778	$ 42,696,636	80,359,211	125,502,807
Deferred revenue			26,274,362		26,274,362		$ 77,769,629
Collaboration and License agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Initial transaction price	$ 252,600,000
Janssen | License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement date	Oct. 3, 2018
Janssen | License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development, regulatory and sales milestones payments	$ 1,600,000,000
Janssen | Research Collaboration and Option Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement date	Oct. 3, 2018
Number of additional targets for development, regulatory and sales milestone payments | Target	3
Janssen | Collaboration Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development, regulatory and sales milestones payments	$ 1,900,000,000
Janssen | JNJ-3989 (ARO-HBV) Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment	$ 25,000,000		25,000,000		25,000,000
Number of distinct performance obligations | Obligation	1
Revenues			6,900,000	42,300,000	57,900,000	124,800,000
Contract assets			0		0
Deferred revenue			26,300,000		26,300,000
Janssen | ARO-JNJ1
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues			400,000	$ 400,000	2,400,000	$ 400,000
Contract assets			1,700,000		1,700,000
Deferred revenue			$ 0		$ 0
JJDC | Common Stock Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement date	Oct. 3, 2018
Proceeds from the issuance of common stock	$ 75,000,000
Janssen and JJDC | Collaboration and License agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash received as due under collaboration agreement	$ 175,000,000

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Detail) - USD ($)	Jun. 30, 2020	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Computers, office equipment and furniture	$ 661,927	$ 637,577
Research equipment	19,514,871	12,932,304
Software	293,189	147,254
Leasehold improvements	24,883,656	21,579,415
Total gross fixed assets	45,353,643	35,296,550
Less: Accumulated depreciation and amortization	(14,963,936)	(12,081,651)
Property and equipment, net	$ 30,389,707	$ 23,214,899

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Property Plant And Equipment [Abstract]
Depreciation and amortization expense for property and equipment	$ 1,111,293	$ 578,342	$ 2,892,551	$ 2,081,447

Investments - Summary of Short-

Investments - Summary of Short-term and Long-term Investments (Detail) - USD ($)	Jun. 30, 2020	Sep. 30, 2019
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	$ 245,239,144	$ 81,075,887
Gross Unrealized Gains	7,033,593	1,097,842
Gross Unrealized Losses	(14,833)
Fair Value	252,257,904	82,173,729
Commercial Notes Due Within One Year
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	67,709,263	36,899,894
Gross Unrealized Gains	1,188,416	222,584
Fair Value	68,897,679	37,122,478
Commercial Notes Due Within One Through Three Years
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	177,529,881	44,175,993
Gross Unrealized Gains	5,845,177	875,258
Gross Unrealized Losses	(14,833)
Fair Value	$ 183,360,225	$ 45,051,251

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 425,107	$ 425,107	$ 1,275,322	$ 1,275,322
Amortization of license agreements remainder of fiscal year 2020	425,107		425,107
Amortization of license agreements in 2021	1,700,429		1,700,429
Amortization of license agreements in 2022	1,700,429		1,700,429
Amortization of license agreements in 2023	1,700,429		1,700,429
Amortization of license agreements in 2024	1,700,429		1,700,429
Amortization of license agreements, thereafter	8,561,435		$ 8,561,435
Novartis | Licensing Agreement
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets			21 years
Finite-lived intangible assets, accumulated amortization	791,495		$ 791,495
Novartis | Patents
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets			14 years
Finite-lived intangible assets, accumulated amortization	$ 8,277,460		$ 8,277,460

Intangible Assets - Schedule of

Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Intangible Assets Net Excluding Goodwill [Abstract]
Intangible assets subject to amortization, beginning balance			$ 17,063,580
Intangible assets subject to amortization, Amortization	$ (425,107)	$ (425,107)	(1,275,322)	$ (1,275,322)
Intangible assets subject to amortization, ending balance	$ 15,788,258		$ 15,788,258

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Aug. 05, 2020	Dec. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Class Of Stock [Line Items]
Capital stock authorized for issuance			150,000,000
Common stock, shares authorized			145,000,000		145,000,000
Common stock, par value			$ 0.001		$ 0.001
Preferred stock, shares authorized			5,000,000
Preferred stock, par value			$ 0.001
Common stock, shares outstanding			102,250,872		95,506,271
Net proceeds from common stock after deducting advisory fees and offering expenses		$ 250,500,000	$ 250,478,974	$ 60,521,729
Public Offering
Class Of Stock [Line Items]
Shares issued to institutional investors		4,600,000
Aggregate purchase price paid by investors		$ 58,000,000
Net proceeds from common stock after deducting advisory fees and offering expenses		$ 266,800,000
Stock issued, price per share		$ 250.5
ATM Agreement | Subsequent Event | Maximum
Class Of Stock [Line Items]
Common stock shares value reserved for future issuance	$ 250,000,000
Percentage of commission to sales agent	3.00%
2004 Equity Incentive Plan, 2013 Equity Incentive Plan, and Inducement Grants
Class Of Stock [Line Items]
Common Stock, Share reserve for issuance			8,252,796

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Jun. 30, 2020	Jun. 30, 2019
Other Commitments [Line Items]
Contingent liabilities	$ 0
Future commitments	83,000,000
Commitments expected to be incurred in fiscal 2020	20,500,000
Commitments expected to be incurred beyond fiscal 2020	62,500,000
Technology License Commitments
Other Commitments [Line Items]
Accrued milestone payments	0	$ 0
Technology License Commitments | ARO-ENaC Program
Other Commitments [Line Items]
Accrued milestone payments	$ 900,000

Leases - Additional Information

Leases - Additional Information (Detail)	1 Months Ended					3 Months Ended	9 Months Ended
	May 31, 2020ft²	Mar. 31, 2020USD ($)ft²	Apr. 30, 2019USD ($)ft²Option	Jan. 31, 2019ft²	Jan. 31, 2016ft²	Jun. 30, 2020USD ($)Option	Jun. 30, 2020USD ($)Option	Sep. 30, 2019USD ($)
Lessee Lease Description [Line Items]
Estimated lease payments								$ 22,385,552
Estimated lease payments						$ 32,992,420	$ 32,992,420
Operating lease cost						800,000	1,700,000
Variable lease cost						200,000	600,000
Short-term lease cost						0	0
Operating lease cash payments						$ 500,000	$ 1,100,000
Weighted-average remaining lease term						9 years 7 months 6 days	9 years 7 months 6 days
Weighted-average discount rate						8.40%	8.40%
Research Facility in Madison | Wisconsin
Lessee Lease Description [Line Items]
Office space leases, in square feet | ft²					60,000
Lease expiration date	Sep. 30, 2031				Sep. 30, 2026
Operating lease renewal term						5 years	5 years
Number of options to renew | Option						2	2
Additional office space for lease | ft²	26,000			14,000
Operating lease expiration month and year				2029-09
Estimated lease payments						$ 26,200,000	$ 26,200,000
Colorado Owner, LLC | Corporate Headquarters In Pasadena | California
Lessee Lease Description [Line Items]
Lease term			91 months
Office space leases, in square feet | ft²			24,000
Lease payments, commencement date			Sep. 30, 2019
Estimated lease payments			$ 8,700,000
Lease expiration date			Apr. 30, 2027
Payments for leasehold improvements, net of tenant improvement allowances			$ 3,500,000
Operating lease renewal term			5 years
Number of options to renew | Option			1
Halozyme, Inc. | California | Sublease Agreement
Lessee Lease Description [Line Items]
Office space leases, in square feet | ft²		21,000
Lease expiration date		Jan. 14, 2023
Estimated lease payments		$ 2,000,000
Sublease commencement date		Apr. 1, 2020

Leases - Summary of Maturities

Leases - Summary of Maturities of Operating Lease Liabilities on an Undiscounted Basis (Detail)	Jun. 30, 2020USD ($)
Leases [Abstract]
2020 (remainder of fiscal year)	$ 681,214
2021	3,091,900
2022	3,853,290
2023	3,406,754
2024	3,269,674
2025 and thereafter	18,689,588
Total lease payments	32,992,420
Less imputed interest	(11,620,743)
Total operating lease liabilities (includes current portion)	$ 21,371,677

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments Under Operating Leases (Detail)	Sep. 30, 2019USD ($)
Leases [Abstract]
2020	$ 1,521,451
2021	2,256,379
2022	2,521,446
2023	2,590,558
2024	2,661,512
2025 and thereafter	10,834,206
Total	$ 22,385,552

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options outstanding	4,529,564		4,529,564		4,773,670
Number of options outstanding, granted			787,500
RSU awards vesting, description			At vesting, each outstanding RSU will be exchanged for one share of the Company’s Common Stock. RSU recipients may elect to net share settle upon vesting, in which case the Company pays the employee’s income taxes due upon vesting and withholds a number of shares of Common Stock of equal value.  RSU awards generally vest subject to the satisfaction of service requirements or the satisfaction of both service requirements and achievement of certain performance targets.
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 2,659,265	$ 1,016,206	$ 6,796,175	$ 2,823,706
Grant date fair value of the options granted	3,421,181	1,316,220	30,020,524	9,453,469
Intrinsic value of options exercised	9,529,237	9,349,226	39,775,062	17,471,520
Unrecognized pre-tax compensation expense	35,021,715		$ 35,021,715
Weighted average period to recognize pre-tax compensation expense			3 years 3 months 18 days
Dividend yield			0.00%
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of restricted stock units outstanding, granted			2,486,646
Stock-based compensation expense	7,386,943	$ 941,788	$ 20,713,488	$ 4,453,169
Weighted average period to recognize pre-tax compensation expense			3 years 3 months 18 days
Unrecognized pre-tax compensation expense	$ 87,634,315		$ 87,634,315
2004 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserve for issuance	744,250		744,250
2004 Equity Incentive Plan | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options outstanding	744,250		744,250
2013 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserve for issuance	5,652,008		5,652,008
2013 Incentive Plan | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options outstanding	2,672,851		2,672,851
Number of options outstanding, granted	0		310,500
2013 Incentive Plan | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of restricted stock units outstanding	2,583,000		2,583,000
Number of restricted stock units outstanding, granted	0		1,749,071
Outside Of Equity Compensation Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserve for issuance	1,112,463		1,112,463
Outside Of Equity Compensation Plans | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options outstanding, granted	134,000		477,000
Outside Of Equity Compensation Plans | Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserve for issuance	744,075		744,075
Number of restricted stock units outstanding, granted	153,000		737,575

Stock-Based Compensation - Summ

Stock-Based Compensation - Summarize Information about Stock Options (Detail) - USD ($)	9 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, beginning balance	4,773,670
Number of Options Outstanding, Granted	787,500
Number of Options Outstanding, Cancelled	(42,409)
Number of Options Outstanding, Exercised	(989,197)
Number of Options Outstanding, ending balance	4,529,564
Number of Options Outstanding, Exercisable	2,928,765
Weighted-Average Exercise Price Per Share, beginning balance	$ 8.16
Weighted-Average Exercise Price Per Share, Granted	50.42
Weighted-Average Exercise Price Per Share, Cancelled	25.04
Weighted-Average Exercise Price Per Share, Exercised	6.54
Weighted-Average Exercise Price Per Share, ending balance	15.71
Weighted-Average Exercise Price Per Share, Exercisable	$ 7.66
Weighted-Average Remaining Contractual Term	6 years 2 months 12 days
Weighted-Average Remaining Contractual Term, Exercisable	4 years 9 months 18 days
Aggregate Intrinsic Value	$ 133,654,814
Aggregate Intrinsic Value, Exercisable	$ 104,700,213

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used to Value Stock Options (Detail) - $ / shares	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Risk-free interest rate, minimum	0.40%	1.90%
Risk-free interest rate, maximum	1.80%	3.10%
Volatility		115.00%
Volatility, minimum	90.50%
Volatility, maximum	91.90%
Expected life (in years)	6 years 3 months	6 years 3 months
Weighted average grant date fair value per share of options granted	$ 38.12	$ 12.21

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSUs Activity (Detail) - Restricted Stock Units (RSUs)	9 Months Ended
	Jun. 30, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs, Unvested, beginning of period | shares	2,062,833
Number of RSUs, Granted | shares	2,486,646
Number of RSUs, Vested | shares	(1,155,404)
Number of RSUs, Forfeited | shares	(67,000)
Number of RSUs, Unvested, End of period | shares	3,327,075
Weighted-Average Grant Date Fair Value, beginning balance | $ / shares	$ 9.43
Weighted-Average Grant Date Fair Value, Granted | $ / shares	57.04
Weighted-Average Grant Date Fair Value, Vested | $ / shares	9.65
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	31.78
Weighted-Average Grant Date Fair Value, ending balance | $ / shares	$ 44.49

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurements for Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Jun. 30, 2020	Sep. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 252,257,904	$ 82,173,729
Contingent consideration	0	0
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	219,322,617	221,804,128
Short-term investments	68,897,679	37,122,478
Long-term investments	183,360,225	45,051,251
Fair Value, Measurements, Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	219,322,617	221,804,128
Short-term investments	68,897,679	37,122,478
Long-term investments	$ 183,360,225	$ 45,051,251

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 30, 2020	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Contingent consideration obligations	$ 0	$ 0