Puma Biotechnology (PBYI) 10-Q 9 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 06, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	PBYI
Entity Registrant Name	PUMA BIOTECHNOLOGY, INC.
Entity Central Index Key	1,401,667
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		37,529,536

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 79,717	$ 194,494
Marketable securities	26,620	34,982
Accounts receivable, net	3,890
Inventory	89
Prepaid expenses and other, current	9,281	6,998
Total current assets	119,597	236,474
Property and equipment, net	4,714	5,153
Prepaid expenses and other, long-term	3,851	6,846
Intangible assets, net	49,379
Restricted cash	4,317	4,317
Total assets	181,858	252,790
Current liabilities:
Accounts payable	17,644	20,035
Accrued expenses	79,608	17,426
Total current liabilities	97,252	37,461
Deferred rent	5,438	5,505
Total liabilities	102,690	42,966
Commitments and contingencies (Note 8)
Stockholders' equity:
Common stock - $.0001 par value; 100,000,000 shares authorized; 37,384,975 shares issued and outstanding at September 30, 2017 and 36,826,010 issued and outstanding at December 31, 2016	4	4
Additional paid-in capital	1,109,212	1,006,344
Receivable from exercise of stock options	(5,653)
Accumulated other comprehensive loss	(7)	(13)
Accumulated deficit	(1,024,388)	(796,511)
Total stockholders' equity	79,168	209,824
Total liabilities and stockholders' equity	$ 181,858	$ 252,790

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	37,384,975	36,826,010
Common stock, shares outstanding	37,384,975	36,826,010

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Product Revenue, net	$ 6,077		$ 6,077
Operating costs and expenses:
Cost of sales	1,526		1,526
Selling, general and administrative	32,489	$ 14,022	75,819	$ 37,326
Research and development	49,502	51,977	157,556	166,400
Total operating expense	83,517	65,999	234,901	203,726
Loss from operations	(77,440)	(65,999)	(228,824)	(203,726)
Other (expenses) income:
Interest income	305	214	1,035	756
Other (expenses) income	(45)	4	(88)	(380)
Total other (expenses) income	260	218	947	376
Net loss	(77,180)	(65,781)	(227,877)	(203,350)
Net loss applicable to common stock	$ (77,180)	$ (65,781)	$ (227,877)	$ (203,350)
Net loss per common share—basic and diluted	$ (2.07)	$ (2.02)	$ (6.15)	$ (6.26)
Weighted-average common shares outstanding—basic and diluted	37,214,002	32,497,168	37,046,765	32,489,584

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (77,180)	$ (65,781)	$ (227,877)	$ (203,350)
Other comprehensive income (loss)
Unrealized gain (loss) on available-for-sale securities	18	(28)	6	150
Comprehensive loss	$ (77,162)	$ (65,809)	$ (227,871)	$ (203,200)

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Receivables from the Exercises of Options	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2016	$ 209,824	$ 4	$ 1,006,344		$ (13)	$ (796,511)
Beginning Balance (in shares) at Dec. 31, 2016	36,826,010	36,826,010
Stock-based compensation	$ 83,213		83,213
Exercises of stock options/issuances of RSUs	$ 14,002		19,655	$ (5,653)
Exercises of stock options/issuances of RSUs (in shares)	419,504	558,965
Unrealized gain on available-for-sale securities	$ 6				6
Net loss	(227,877)					(227,877)
Ending Balance at Sep. 30, 2017	$ 79,168	$ 4	$ 1,109,212	$ (5,653)	$ (7)	$ (1,024,388)
Ending Balance (in shares) at Sep. 30, 2017	37,384,975	37,384,975

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net loss	$ (227,877)	$ (203,350)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,451	565
Built-out allowance received from landlord		2,997
Stock-based compensation	83,213	87,990
Disposal of leasehold improvements		368
Changes in operating assets and liabilities:
Accounts receivable, net	(3,890)
Inventory	(89)
Other receivables		(1,179)
Prepaid expenses and other	712	2,832
Accounts payable	(2,496)	3,075
Accrued expenses	12,182	2,082
Accrual of deferred rent	(67)	3,891
Net cash used in operating activities	(136,861)	(100,729)
Investing activities:
Purchase of property and equipment	(286)	(3,730)
Restricted cash		(3)
Expenditures for leasehold improvements		(2,997)
Purchase of available-for-sale securities	(79,728)	(81,794)
Sale/maturity of available-for-sale securities	88,096	209,874
Net cash provided by investing activities	8,082	121,350
Financing activities:
Net proceeds from the exercise of options	14,002	351
Net cash provided by financing activities	14,002	351
Net (decrease) increase in cash and cash equivalents	(114,777)	20,972
Cash and cash equivalents, beginning of period	194,494	31,569
Cash and cash equivalents, end of period	79,717	$ 52,541
Supplemental disclosures of non-cash investing and financing activities:
Property and equipment purchases in accounts payable	105
Licensor fee due in accrued expenses	50,000
Receivables related to stock option exercises	$ 5,653

Business and Basis of Presentat

Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business and Basis of Presentation	Note 1—Business and Basis of Presentation: Business: Puma Biotechnology, Inc., or Puma, is a biopharmaceutical company based in Los Angeles, California with a focus on the development and commercialization of innovative products to enhance cancer care. The Company in-licenses the global development and commercialization rights to three drug candidates—PB272 (neratinib (oral)), PB272 (neratinib (intravenous)) and PB357. Neratinib is a potent irreversible tyrosine kinase inhibitor that blocks signal transduction through the epidermal growth factor receptors, HER1, HER2 and HER4. Currently, the Company is primarily focused on the development and commercialization of the oral version of neratinib, and its most advanced drug candidates are directed at the treatment of HER2-positive breast cancer. The Company believes that neratinib has clinical application in the treatment of several other cancers as well, including non-small cell lung cancer and other tumor types that over-express or have a mutation in HER2. In November 2012, the Company established and incorporated Puma Biotechnology Ltd., a wholly owned subsidiary, for the sole purpose of serving as Puma’s legal representative in the United Kingdom and the European Union in connection with Puma’s clinical trial activity in those countries. Basis of Presentation: The Company is focused on developing and commercializing neratinib for the treatment of patients with human epidermal growth factor receptor type 2, or HER2-positive, breast cancer, HER2 mutated non-small cell lung cancer, HER2-negative breast cancer that has a HER2 mutation and other solid tumors that have an activating mutation in HER2. The Company has reported a net loss of approximately $77.2 million and $227.9 million for the three and nine months ended September 30, 2017, and negative cash flows from operations of approximately $136.9 million for the nine months ended September 30, 2017. Management believes that the Company will continue to incur net losses and negative net cash flows from operating activities through the drug development process and early commercialization. The accompanying unaudited condensed consolidated interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC, for interim financial information. Accordingly, the unaudited condensed consolidated financial statements do not include all information and footnotes required by GAAP for complete annual financial statements. In the opinion of management, the accompanying unaudited condensed consolidated interim financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation. Interim operating results are not necessarily indicative of results that may be expected for the year ending December 31, 2017, or for any subsequent period. These unaudited condensed consolidated interim financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. The condensed consolidated balance sheet at December 31, 2016 has been derived from the audited consolidated financial statements included in the Annual Report on Form 10-K for the fiscal year ended December 31, 2016. The Company has incurred significant operating losses since its inception, which raises substantial doubt about its ability to continue as a going concern. On July 17, 2017, the Company received U.S. Food and Drug Administration, or FDA, approval for its first product, NERLYNX® (neratinib), formerly known as PB272 (neratinib (oral)), for the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. NERLYNX recently became available by prescription in the United States, and the Company has commenced commercialization. The Company is exploring methods by which to commercially launch neratinib in the European Union should approval be granted by the European Medicines Agency, or EMA. Commercialization in the United States, and if approved, in the European Union, may require funding in addition to the cash and cash equivalents and marketable securities totaling approximately $106.3 million available at September 30, 2017. While the consolidated financial statements have been prepared on a going concern basis, the Company continues to remain dependent on its ability to obtain sufficient funding to sustain operations and successfully commercialize neratinib in the United States, and, if approved, launch in the European Union. While the Company has been successful in raising financing in the past, there can be no assurance that it will be able to do so in the future. The Company’s ability to obtain funding may be adversely impacted by uncertain market conditions, unfavorable decisions of regulatory authorities or adverse clinical trial results. The outcome of these matters cannot be predicted at this time. The Company’s continued operations will depend on its ability to successfully commercialize NERLYNX, the Company’s only product, and to raise funds through various potential sources, such as equity and debt financing. Since its inception through September 30, 2017, the Company’s financing was primarily through public offerings of Company common stock and private equity placements. The Company sold shares of its common stock through an underwritten public offering in October 2016 (see Note 6 to the Annual Report on Form 10-K for the year ended December 31, 2016). As a result, the Company received net proceeds of approximately $161.9 million. The Company may need additional financing before it can achieve profitability, if ever. There can be no assurance that additional capital will be available on favorable terms or at all or that any additional capital that the Company is able to obtain will be sufficient to meet its needs. If it is unable to raise additional capital, the Company could likely be forced to curtail desired development activities, which will delay the development of its product candidates.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Significant Accounting Policies	Note 2—Significant Accounting Policies: The significant accounting policies followed in the preparation of these unaudited condensed consolidated financial statements are as follows: Use of Estimates: The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the balance sheet, and reported amounts of expenses for the period presented. Accordingly, actual results could differ from those estimates. Significant estimates include accrued expenses for the cost of services provided by consultants who manage clinical trials and conduct research and clinical trials on behalf of the Company that are billed on a delayed basis. As the actual costs become known, the Company adjusts its estimated cost in that period. The value of stock-based compensation includes estimates based on future events, which are difficult to predict. It is at least reasonably possible that a change in the estimates used to record accrued expenses and to value the stock-based compensation will occur in the near term. Principles of Consolidation: The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation. Cash and Cash Equivalents: The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. Cash equivalents are carried at cost, which approximates fair value. Investment Securities: The Company classifies all investment securities (short term) as available-for-sale, as the sale of such securities may be required prior to maturity to implement management’s strategies. These securities are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis. A decline in the market value of any available-for-sale security below cost that is determined to be other than temporary results in a revaluation of its carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. Accounts Receivable: Accounts receivable are recorded net of customer allowances for distribution fees, prompt payment discounts, chargebacks, and doubtful accounts. Allowances for distribution fees, prompt payment discounts and chargebacks are based on contractual terms. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. At September 30, 2017, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented. License Fees and Royalties: The Company expenses amounts paid to acquire licenses associated with products under development when the ultimate recoverability of the amounts paid is uncertain and the technology has no alternative future use when acquired. Acquisitions of technology licenses are charged to expense or capitalized based upon the asset achieving technological feasibility in accordance with management’s assessment regarding the ultimate recoverability of the amounts paid and the potential for alternative future use. The Company has determined that technological feasibility for its product candidates is reached when the requisite regulatory approvals are obtained to make the product available for sale. The Company capitalizes technology licenses upon reaching technological feasibility. In connection with the FDA approval of NERLYNX in July 2017, the Company triggered a one-time milestone payment pursuant to its 2014 license agreement with Pfizer Inc., or the Licensor. The Company capitalized the milestone payment as an intangible asset and is amortizing the asset on a straight-line basis over the estimated useful life of the licensed patent through 2030. The Company recorded amortization expense related to its intangible asset of $0.6 million for the three months ended September 30, 2017. As of September 30, 2017, estimated future amortization expense related to the Company’s intangible asset was $1.0 million for the remainder of 2017, approximately $3.9 million for each year starting 2018 through 2029, and $1.0 million for 2030. Royalties incurred in connection with the Company’s license agreement with the Licensor, as disclosed in Note 9-Commitments and Contingencies, are expensed to cost of sales as revenue from product sales is recognized. Intangible Assets: The Company maintains definite-lived intangible assets related to the Licensor agreement. These assets are amortized over their remaining useful lives, which are estimated based on the shorter of the remaining patent life or the estimated useful life of the underlying product. Intangible assets are amortized using the economic consumption method if anticipated future revenues can be reasonably estimated. The straight-line method is used when future revenues cannot be reasonably estimated. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstance suggest that impairment may exist. Events that could result in an impairment, or trigger an interim impairment assessment, include the receipt of additional clinical or nonclinical data regarding one of the Company’s drug candidates or a potentially competitive drug candidate, changes in the clinical development program for a drug candidate, or new information regarding potential sales for the drug. If impairment indicators are present or changes in circumstance suggest that impairment may exist, the Company performs a recoverability test by comparing the sum of the estimated undiscounted cash flows of each intangible asset to its carrying value on the condensed consolidated balance sheet. If the undiscounted cash flows used in the recoverability test are less than the carrying value, the Company would determine the fair value of the intangible asset and recognize an impairment loss if the carrying value of the intangible asset exceeds its fair value. Inventory: The Company values its inventories at the lower of cost or estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and it writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment is first identified. Such impairment charges, should they occur, are recorded within the cost of sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required, which would be recorded as a cost of sales in the consolidated statements of operations and comprehensive loss. The Company capitalizes inventory costs associated with the Company’s products after regulatory approval, if any, when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized. Inventory acquired prior to receipt of marketing approval of a product candidate is expensed as research and development expense as incurred. Inventory that can be used in either the production of clinical or commercial product is expensed as research and development expense when selected for use in a clinical trial. Starter kits, provided to patients prior to insurance approval, are expensed by the Company to sales and marketing expense as incurred. Revenue Recognition: The Company adopted Accounting Standards Codification (“ASC”) Topic 606 - Revenue from Contracts with Customers (“Topic 606”) on January 1, 2017. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements, and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of the promised goods or services, in an amount that reflects the consideration which the entity expects to be entitled in exchange for those goods or services. The Company had no contracts with customers until the FDA approved NERLYNX on July 17, 2017. Subsequent to receiving FDA approval, the Company entered into a limited number of arrangements with specialty pharmacies (“SPs”) and specialty distributors (“SDs”) in the U.S. (collectively, its “Customers”) to distribute NERLYNX. These arrangements are the Company’s initial contracts with customers. The Company has determined that these sales channels with customers are similar. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to arrangements that meet the definition of a contract under Topic 606, including when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. For a complete discussion of accounting for product revenue, see Product Revenue, Net Product Revenue, Net: The Company sells NERLYNX to a limited number of SPs and SDs in the U.S. (collectively, its “Customers”). These Customers subsequently resell the Company’s products to patients and certain medical centers or hospitals. In addition to distribution agreements with Customers, the Company enters into arrangements with health care providers and payors that provide for government mandated and/or privately negotiated rebates, chargebacks, and discounts with respect to the purchase of the Company’s products. The Company recognizes revenue on product sales when the Customer obtains control of the Company's product, which occurs at a point in time (upon delivery). Product revenue is recorded net of applicable reserves for variable consideration, including discounts and allowances. The Company’s payment terms range between 10 and 60 days. Shipping and handling costs for product shipments occur prior to the customer obtaining control of the goods, and are recorded in cost of sales. If taxes should be collected from Customers relating to product sales and remitted to governmental authorities, they will be excluded from revenue. The Company expenses incremental costs of obtaining a contract when incurred, if the expected amortization period of the asset that the Company would have recognized is one year or less. However, no such costs were incurred during the three months ended September 30, 2017. Reserves for Variable Consideration: Revenue from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established. Components of variable consideration include trade discounts and allowances, product returns, provider chargebacks and discounts, government rebates, payor rebates, and other incentives, such as voluntary patient assistance, and other allowances that are offered within contracts between the Company and its Customers, payors, and other indirect customers relating to the Company’s sale of its products. These reserves, as detailed below, are based on the amounts earned, or to be claimed on the related sales, and are classified as reductions of accounts receivable (if the amount is payable to the Customer) or a current liability (if the amount is payable to a party other than a Customer). These estimates take into consideration a range of possible outcomes which are probability-weighted in accordance with the expected value method in Topic 606 for relevant factors such as current contractual and statutory requirements, specific known market events and trends, industry data, and forecasted customer buying and payment patterns. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the respective underlying contracts. The amount of variable consideration which is included in the transaction price may be constrained, and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. The Company’s analyses also contemplated application of the constraint in accordance with the guidance, under which it determined a material reversal of revenue would not occur in a future period for the estimates detailed below as of September 30, 2017 and, therefore, the transaction price was not reduced further during the three months ended September 30, 2017. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from the Company’s estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known. Trade Discounts and Allowances: The Company generally provides Customers with discounts which include incentive fees that are explicitly stated in the Company’s contracts and are recorded as a reduction of revenue in the period the related product revenue is recognized. In addition, the Company compensates (through trade discounts and allowances) its Customers for sales order management, data, and distribution services. However, the Company has determined such services received to date are not distinct from the Company’s sale of products to the Customer and, therefore, these payments have been recorded as a reduction of revenue within the statement of operations and comprehensive loss through September 30, 2017, as well as a reduction to trade receivables, net on the condensed consolidated balance sheets. Product Returns: Consistent with industry practice, the Company offers the SPs and SDs limited product return rights for damages and expiring product, provided it is within a specified period around the product expiration date as set forth in the applicable individual distribution agreement. The Company estimates the amount of its product sales that may be returned by its Customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as reductions to trade receivables, net on the condensed consolidated balance sheets. The Company currently estimates product return liabilities using available industry data and its own sales information, including its visibility into the inventory remaining in the distribution channel. The Company has not received any returns to date and believes that returns of its products will be minimal. Provider Chargebacks and Discounts: Chargebacks for fees and discounts to providers represent the estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices charged to Customers who directly purchase the product from the Company. Customers charge the Company for the difference between what they pay for the product and the ultimate selling price to the qualified healthcare providers. These reserves are established in the same period that the related revenue is recognized, resulting in a reduction of product revenue and trade receivables, net. Chargeback amounts are generally determined at the time of resale to the qualified healthcare provider by Customers, and the Company generally issues credits for such amounts within a few weeks of the Customer’s notification to the Company of the resale. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at each reporting period-end that the Company expects will be sold to qualified healthcare providers, and chargebacks that Customers have claimed, but for which the Company has not yet issued a credit. Government Rebates: The Company is subject to discount obligations under state Medicaid programs and Medicare. These reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included in accrued expenses and other current liabilities on the condensed consolidated balance sheets. For Medicare, the Company also estimates the number of patients in the prescription drug coverage gap for whom the Company will owe an additional liability under the Medicare Part D program. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimated future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel inventories at the end of each reporting period. Payor Rebates: The Company contracts with certain private payor organizations, primarily insurance companies and pharmacy benefit managers, for the payment of rebates with respect to utilization of its products. The Company estimates these rebates and records such estimates in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability. Other Incentives: Other incentives which the Company offers include voluntary patient assistance programs, such as the co-pay assistance program, which are intended to provide financial assistance to qualified commercially-insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay assistance is based on an estimate of claims and the cost per claim that the Company expects to receive associated with product that has been recognized as revenue, but remains in the distribution channel inventories at the end of each reporting period. The adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included as a component of accrued expenses and other current liabilities on the condensed consolidated balance sheets. Assets Measured at Fair Value on a Recurring Basis: Accounting Standards Codification, or ASC, 820, Fair Value Measurement Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets. Level 3: Valuations derived from valuation techniques in which one or more significant inputs are unobservable. Following are the major categories of assets measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016, using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3) (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds — 26,620 — 26,620 $ 68,911 $ 26,620 $ — $ 95,531 December 31, 2016 Level 1 Level 2 Level 3 Total Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper — 5,998 — 5,998 Marketable securities - corporate bonds — 28,984 — 28,984 $ 188,543 $ 34,982 $ — $ 223,525 The Company’s investments in commercial paper, corporate bonds and U.S. government securities are exposed to price fluctuations. The fair value measurements for commercial paper, corporate bonds and U.S. government securities are based upon the quoted prices of similar items in active markets multiplied by the number of securities owned. The Company invests its excess cash in commercial paper and debt instruments of corporations. As of September 30, 2017, the Company’s short-term investments had a weighted average maturity of less than one year. The following tables summarize the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Estimated September 30, 2017 (in years) cost Gains Losses fair value Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds Less than 1 26,620 — (7 ) 26,613 $ 95,531 $ — $ (7 ) $ 95,524 Maturity Amortized Unrealized Estimated December 31, 2016 (in years) cost Gains Losses fair value Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper Less than 1 5,998 — — 5,998 Marketable securities - corporate bonds Less than 1 28,984 — (13 ) 28,971 $ 223,525 $ — $ (13 ) $ 223,512 Concentration of Risk: Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash and cash equivalents. The Company’s cash and cash equivalents in excess of the Federal Deposit Insurance Corporation and the Securities Investor Protection Corporation insured limits at September 30, 2017, were approximately $85.4 million. The Company does not believe it is exposed to any significant credit risk due to the quality of the financial instruments in which the money is held. Pursuant to the Company’s internal investment policy, investments must be rated A-1/P-1 or better by Standard and Poor’s Corporation and Moody’s Investors Service at the time of purchase. Property and Equipment: Property and equipment are recorded at cost and depreciated over estimated useful lives ranging from three to five years using the straight-line method. Leasehold improvements are recorded at cost and amortized over the shorter of their useful lives or the term of the lease by use of the straight-line method. Maintenance and repair costs are charged to operations as incurred. The Company assesses the impairment of long-lived assets, primarily property and equipment, whenever events or changes in business circumstances indicate that carrying amounts of the assets may not be fully recoverable. When such events occur, management determines whether there has been impairment by comparing the asset’s carrying value with its fair value, as measured by the anticipated undiscounted net cash flows of the asset. Should impairment exist, the asset is written down to its estimated fair value. The Company has not recognized any impairment losses through September 30, 2017. Research and Development Expenses: Research and development expenses are charged to operations as incurred. The major components of research and development costs include clinical manufacturing costs, clinical trial expenses, consulting and other third-party costs, salaries and employee benefits, stock-based compensation expense, supplies and materials, and allocations of various overhead costs. Clinical trial expenses include, but are not limited to, investigator fees, site costs, comparator drug costs, and clinical research organization, or CRO, costs. In the normal course of business, the Company contracts with third parties to perform various clinical trial activities in the ongoing development of potential products. The financial terms of these agreements are subject to negotiation and variations from contract to contract and may result in uneven payment flows. Payments under the contracts depend on factors such as the achievement of certain events, the successful enrollment of patients and the completion of portions of the clinical trial or similar conditions. The Company’s accruals for clinical trials are based on estimates of the services received and efforts expended pursuant to contracts with numerous clinical trial sites, cooperative groups and CROs. The objective of the Company’s accrual policy is to record expenses in the unaudited condensed consolidated financial statements as the actual services are performed and efforts expended. As actual costs become known, the Company records the actual expenses in that period. In instances where the Company enters into agreements with third parties for clinical trials and other consulting activities, upfront amounts are recorded to prepaid expenses and other in the accompanying unaudited condensed consolidated balance sheets and expensed as services are performed or as the underlying goods are delivered. If the Company does not expect the services to be rendered or goods to be delivered, any remaining capitalized amounts for non-refundable upfront payments are charged to expense immediately. Amounts due under such arrangements may be either fixed fee or fee for service, and may include upfront payments, monthly payments and payments upon the completion of milestones or receipt of deliverables. Costs related to the acquisition of technology rights and patents for which development work is still in process are charged to operations as incurred and considered a component of research and development costs. Stock-Based Compensation: Stock option awards: ASC 718, Compensation — Stock Compensation Restricted stock units: The restricted stock units, or RSUs, Net Loss per Common Share: Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of common shares outstanding during the periods presented as required by ASC 260, Earnings per Share Deferred Rent: The Company has entered into operating lease agreements for its corporate offices in Los Angeles and South San Francisco that contain provisions for future rent increases, leasehold improvement allowances and rent abatements. The Company records monthly rent expense equal to the total of the payments due over the lease term, divided by the number of months of the lease term. The difference between the rent expense recorded and the amount paid is credited or charged to deferred rent, which is reflected as a separate line item in the accompanying unaudited condensed consolidated balance sheets. Additionally, the Company recorded as deferred rent the cost of the leasehold improvements paid by the landlord, which is amortized on a straight-line basis over the term of the lease. Issuance of Common Stock Upon Exercise of Stock Option Grants: When a stock option grant is exercised, the Company notifies its transfer agent to release the required number of shares of common stock from the reserve for the Puma Biotechnology, Inc. 2011 Incentive Award Plan, as amended, or the 2011 Plan. The Company records the transaction for the cash received and the issuance of common shares. Should there be a delay in the cash receipts due to the settlement period, the Company records a receivable from the exercise of an option as a reduction of stockholders’ equity on the unaudited condensed consolidated balance sheet. Recently Issued Accounting Standards: In May 2014, the Financial Accounting Standards Board, FASB, issued a new accounting standard that amends the guidance for the recognition of revenue from contracts with customers to transfer goods and services. The FASB has subsequently issued additional, clarifying standards to address issues arising from implementation of the new revenue recognition standard. The new revenue recognition standard and clarifying standards are effective for interim and annual periods beginning on January 1, 2018, but could have been adopted early beginning January 1, 2017. The Company has chosen to adopt this standard in 2017 as it began to generate revenue. The Company has also identified and implemented changes to its accounting policies, business processes, and internal controls to support the new accounting and disclosure requirements. In February 2016, the FASB issued Accounting Standards Update, or ASU, No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation: Improvements to Employee Share-Based Payment Accounting, In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows Topic 230 : Classification of Certain Cash Receipts and Cash Payments a consensus of the Emerging Issues Task Force In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows Topic 230 Restricted Cash In January 2017 Business Combinations (Topic 805): Clarifying the Definition of a Business

Prepaid Expenses and Other

Prepaid Expenses and Other	9 Months Ended
	Sep. 30, 2017
Banking And Thrift [Abstract]
Prepaid Expenses and Other	Note 3—Prepaid Expenses and Other: The Company, from time to time, makes payments to certain vendors for which the service relates to future periods. In these cases, the Company classifies these expenses as prepaid and other and amortizes those payments over the period for which the services relate. In some cases, the vendors require an upfront payment to be applied to the final invoices under the agreements. In those cases, if the contract extends beyond the period of one year, the prepayments are classified as long-term. Prepaid expenses and other consisted of the following (in thousands): September 30, 2017 December 31, 2016 Current: CRO services $ 6,724 $ 3,471 Other clinical development 664 1,069 Insurance 255 1,159 Other 1,638 1,299 9,281 6,998 Long-term: CRO services 1,726 5,077 Other clinical development 565 1,243 Insurance 16 40 Other 1,544 486 3,851 6,846 Totals $ 13,132 $ 13,844

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2017
Property Plant And Equipment [Abstract]
Property and Equipment	Note 4—Property and Equipment: Property and equipment consisted of the following (in thousands): Property and Equipment: September 30, 2017 December 31, 2016 Leasehold improvements $ 3,878 $ 3,878 Computer equipment 2,112 1,822 Telephone equipment 296 256 Furniture and fixtures 2,207 2,146 8,493 8,102 Less: accumulated depreciation and amortization (3,779 ) (2,949 ) Totals $ 4,714 $ 5,153

Intangible assets, net

Intangible assets, net	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible assets, net	Note 5—Intangible assets, net: Intangible assets, net consisted of the following (in thousands): September 30, 2017 Estimated useful life Acquired and in-licensed rights $ 50,000 13 Years Less: accumulated amortization (621 ) Total intangible asset, net $ 49,379

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2017
Payables And Accruals [Abstract]
Accrued Expenses	Note 6—Accrued Expenses: Accrued expenses consisted of the following (in thousands): September 30, 2017 December 31, 2016 Accrued CRO services $ 8,323 $ 6,609 Accrued other clinical development 7,243 7,015 Accrued legal fees 2,806 706 Accrued compensation 8,486 3,058 Accrued in-licensed rights 50,000 — Other 2,750 38 Totals $ 79,608 $ 17,426 Accrued CRO services represent the Company’s estimate of such costs and will be adjusted in the period the actual costs become known. Accrued compensation includes estimated bonus and earned but unused vacation for full-time employees. When actual performance bonuses are paid out to employees, the bonus expense will be adjusted to reflect the actual expense for the year. Accrued in-licensed rights represent amounts owed pursuant to the Company’s license agreement with the Licensor. Pursuant to the license agreement, the Company licensed certain intellectual property rights for neratinib and is obligated to make a one-time regulatory milestone payment to the Licensor upon obtaining regulatory approval of its NDA from the FDA. Additionally, vacation is accrued at the rate the employee earns vacation and reduced as vacation is used by the employee.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Stockholders' Equity	Note 7—Stockholders’ Equity: Stock-Based Compensation: The Company’s 2011 Plan was adopted by the board of directors on September 15, 2011. Pursuant to the 2011 Plan, the Company may grant incentive stock options, nonqualified stock options and restricted stock units, as well as other forms of equity-based compensation. Incentive stock options may be granted only to employees, while consultants, employees, officers and directors are eligible for the grant of nonqualified options and restricted stock units under the 2011 Plan. The maximum term of stock options granted under the 2011 Plan is 10 years. The exercise price of incentive stock options granted under the 2011 Plan must be at least equal to the fair value of such shares on the date of grant. Through September 30, 2017, a total of 12,529,412 shares of the Company’s common stock have been reserved for issuance under the 2011 Plan. The Company’s 2017 Employment Inducement Incentive Award Plan, or the 2017 Plan, was adopted by the board of directors on April 27, 2017. Pursuant to the 2017 Plan, the Company may grant stock options and restricted stock units, as well as other forms of equity-based compensation to employees, as an inducement to join the Company. The maximum term of stock options granted under the 2017 Plan is 10 years. The exercise price of stock options granted under the 2017 Plan must be at least equal to the fair market value of such shares on the date of grant. As of September 30, 2017, a total of 1,000,000 shares of the Company’s common stock have been reserved for issuance under the 2017 Plan. As of September 30, 2017, 233,250 shares have been awarded under the 2017 Plan. Employee stock-based compensation for the three and nine months ended September 30, 2017 and 2016 were as follows (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Stock-based compensation: Options - Research and development, or R&D $ 15,825 $ 20,258 $ 54,062 $ 66,376 Selling, general and administrative, or SG&A 5,817 6,802 18,371 18,852 Performance shares - R&D — 68 — 139 Restricted stock units - R&D 2,333 1,754 6,185 1,754 SG&A 2,513 869 4,595 869 Total stock-based compensation expense $ 26,488 $ 29,751 $ 83,213 $ 87,990 Stock Options and Restricted Stock Units: The fair value of options granted to employees was estimated using the Black-Scholes Option Pricing Method (see Note 2—Significant Accounting Policies) with the following weighted-average assumptions used during the nine months ended September 30, 2017 and 2016: 2017 2016 Dividend yield 0.0 % 0.0 % Expected volatility 70.2 % 67.3 % Risk-free interest rate 2.0 % 1.4 % Expected life in years 5.83 5.72 Activity with respect to options granted under the 2011 Plan is summarized as follows: Shares Weighted Average Exercise Price Weighted Contractual Term (years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 6,578,522 $ 87.52 8.0 $ 18,442 Granted 519,791 $ 38.87 Forfeited (272,399 ) $ 50.26 Exercised (419,504 ) $ 46.85 $ 18,366 Expired (111,218 ) $ 117.89 Outstanding at September 30, 2017 6,295,192 $ 87.29 7.4 $ 318,349 Nonvested at September 30, 2017 2,333,232 58.97 8.8 $ 151,369 At September 30, 2017, total estimated unrecognized employee compensation cost related to nonvested stock options and restricted stock units granted prior to that date were approximately $68.7 million and $56.3 million, respectively. These unrecognized expenses are expected to be recognized over a weighted-average period of 1.4 years for stock options and 2.5 years for restricted stock units. The weighted-average grant date fair value of options granted during the nine months ended September 30, 2017 and 2016, were $24.30 per share and $26.79 per share, respectively. Weighted Average Grant-Date Stock options Shares Fair Value Nonvested shares at December 31, 2016 3,106,083 $ 47.78 Granted 519,791 24.30 Vested/Issued (1,020,243 ) 61.53 Forfeited (272,399 ) 30.28 Nonvested shares at September 30, 2017 2,333,232 35.31 Restricted stock units have been awarded to certain employees under the 2011 and 2017 Plan. These awards vest over three years. Weighted Average Grant-Date Restricted stock units Shares Fair Value Nonvested shares at December 31, 2016 630,508 $ 54.35 Granted 569,750 79.82 Vested/Issued (203,892 ) 54.35 Forfeited (40,306 ) 54.35 Nonvested shares at September 30, 2017 956,060 $ 69.53

401(k) Savings Plan

401(k) Savings Plan	9 Months Ended
	Sep. 30, 2017
Postemployment Benefits [Abstract]
401(k) Savings Plan	Note 8—401(k) Savings Plan: During 2012, the Company adopted a 401(k) savings plan for the benefit of its employees. The Company is required to make matching contributions to the 401(k) plan equal to 100% of the first 3% of wages deferred by each participating employee and 50% on the next 2% of wages deferred by each participating employee. The Company incurred expenses for employer matching contributions of approximately $0.6 million and $0.7 million for the nine months ended September 30, 2017 and 2016, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 9—Commitments and Contingencies: Legal Matters The Company is involved in various lawsuits, claims and other legal matters from time to time that arise in the ordinary course of conducting business. The Company records a liability when a particular contingency is probable and estimable. The Company has not accrued for any contingency at September 30, 2017, as the Company does not consider any contingency to be probable or estimable. The Company faces contingencies that are reasonably possible to occur; however, they cannot currently be estimated. While complete assurance cannot be given to the outcome of these proceedings, management does not currently believe that any of these matters, individually or in the aggregate, will have a material adverse effect on the Company’s financial condition, liquidity or results of operations. Legal Proceedings Hsu vs. Puma Biotechnology, Inc., et. al. On June 3, 2015, Hsingching Hsu or the “plaintiff,” individually and on behalf of all others similarly situated, filed a class action lawsuit against us or “the defendants” and certain of our executive officers in the United States District Court for the Central District of California (Case No. 8:15-cv-00865-AG-JCG). On October 16, 2015, lead plaintiff Norfolk Pension Fund filed a consolidated complaint on behalf of all persons who purchased our securities between July 22, 2014 and May 29, 2015. The consolidated complaint alleges that the Company and certain of our executive officers made false or misleading statements and failed to disclose material adverse facts about our business, operations, prospects and performance in violation of Sections 10(b) (and Rule 10b-5 promulgated thereunder) and 20(a) of the Exchange Act. The plaintiff seeks damages, interest, costs, attorneys' fees, and other unspecified equitable relief. On September 30, 2016, the court denied the defendants’ motion to dismiss the consolidated complaint. On June 6, 2017, the lead plaintiff filed a first amended complaint that included new claims about additional statements that plaintiff alleges are false or misleading. On June 19, 2017, defendants moved to dismiss the new claims in the amended complaint. On July 25, 2017, the court denied the motion to dismiss. A trial date is currently set for November 6, 2018. The Company intends to vigorously defend against this matter. Eshelman vs. Puma Biotechnology, Inc., et. al. On February 2, 2016, Fredric N. Eshelman filed a lawsuit against our Chief Executive Officer and President, Alan H. Auerbach, and the Company in the United States District Court for the Eastern District of North Carolina (Case No. 7:16-cv-00018-D). The complaint generally alleges that Mr. Auerbach and the Company made defamatory statements regarding Dr. Eshelman in connection with a proxy contest. Dr. Eshelman seeks compensatory and punitive damages and expenses and costs, including attorneys’ fees. On April 4, 2016, the Company filed a motion to dismiss the complaint. On May 2, 2016, Dr. Eshelman filed a notice of voluntary dismissal of the claims against Mr. Auerbach. On February 6, 2017, the court denied the Company’s motion to dismiss. Discovery ended in September 2017. The Company intends to vigorously defend against Dr. Eshelman’s claims. Derivative Actions On April 12 and April 14, 2016, alleged shareholders filed two derivative lawsuits purportedly on behalf of the Company against certain of our officers and directors in the Superior Court of the State of California, Los Angeles, captioned Xing Xie v. Alan H. Auerbach, No. BC616617, and Kevin McKenney v. Auerbach, No. BC617059. The complaints assert claims for breach of fiduciary duty, unjust enrichment, abuse of control, mismanagement and waste of corporate assets arising from substantially similar allegations as those contained in the securities class action described above. The complaints seek an unspecified sum of damages and equitable relief. The Company intends to vigorously defend against this matter. Stockholder Demand On September 13, 2017, a purported stockholder filed a complaint in the Court of Chancery of the State of Delaware seeking an equitable apportionment of attorneys’ fees in an unspecified amount. The purported stockholder alleges that his actions caused Company’s board of directors to implement certain governance reforms and enhancements to our director compensation program, and that, as a result of his actions, the purported stockholder is entitled to attorneys’ fees in an amount commensurate to those purported benefits. The Company filed an answer to the complaint on October 20, 2017. The Company intends to vigorously defend against this matter. The pending proceedings described in this section involve complex questions of fact and law and will require the expenditure of significant funds and the diversion of other resources to defend. The results of legal proceedings are inherently uncertain, and material adverse outcomes are possible. Royalty Payments Under the Company’s license agreement with the Licensor, pursuant to which the Company licensed certain intellectual property rights for neratinib, the Company is obligated to make a one-time regulatory milestone payment to the Licensor upon obtaining regulatory approval of its NDA from the FDA. The Company is also required to make royalty payments on net product sales, if any.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Note 10—Subsequent Events: The Company entered into a loan agreement with Silicon Valley Bank and Oxford Finance for a term loan of up to $100.0 million, subject to funding in two tranches. The Company received gross proceeds of $50.0 million from the first tranche of the credit facility upon closing on October 31, 2017 and intends to use the funds for general corporate purposes

Significant Accounting Polici18

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates: The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the balance sheet, and reported amounts of expenses for the period presented. Accordingly, actual results could differ from those estimates. Significant estimates include accrued expenses for the cost of services provided by consultants who manage clinical trials and conduct research and clinical trials on behalf of the Company that are billed on a delayed basis. As the actual costs become known, the Company adjusts its estimated cost in that period. The value of stock-based compensation includes estimates based on future events, which are difficult to predict. It is at least reasonably possible that a change in the estimates used to record accrued expenses and to value the stock-based compensation will occur in the near term.
Principles of Consolidation	Principles of Consolidation: The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation.
Cash and Cash Equivalents	Cash and Cash Equivalents: The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. Cash equivalents are carried at cost, which approximates fair value.
Investment Securities	Investment Securities: The Company classifies all investment securities (short term) as available-for-sale, as the sale of such securities may be required prior to maturity to implement management’s strategies. These securities are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis. A decline in the market value of any available-for-sale security below cost that is determined to be other than temporary results in a revaluation of its carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established.
Accounts Receivable	Accounts Receivable: Accounts receivable are recorded net of customer allowances for distribution fees, prompt payment discounts, chargebacks, and doubtful accounts. Allowances for distribution fees, prompt payment discounts and chargebacks are based on contractual terms. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. At September 30, 2017, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented.
License Fees and Royalties	License Fees and Royalties: The Company expenses amounts paid to acquire licenses associated with products under development when the ultimate recoverability of the amounts paid is uncertain and the technology has no alternative future use when acquired. Acquisitions of technology licenses are charged to expense or capitalized based upon the asset achieving technological feasibility in accordance with management’s assessment regarding the ultimate recoverability of the amounts paid and the potential for alternative future use. The Company has determined that technological feasibility for its product candidates is reached when the requisite regulatory approvals are obtained to make the product available for sale. The Company capitalizes technology licenses upon reaching technological feasibility. In connection with the FDA approval of NERLYNX in July 2017, the Company triggered a one-time milestone payment pursuant to its 2014 license agreement with Pfizer Inc., or the Licensor. The Company capitalized the milestone payment as an intangible asset and is amortizing the asset on a straight-line basis over the estimated useful life of the licensed patent through 2030. The Company recorded amortization expense related to its intangible asset of $0.6 million for the three months ended September 30, 2017. As of September 30, 2017, estimated future amortization expense related to the Company’s intangible asset was $1.0 million for the remainder of 2017, approximately $3.9 million for each year starting 2018 through 2029, and $1.0 million for 2030. Royalties incurred in connection with the Company’s license agreement with the Licensor, as disclosed in Note 9-Commitments and Contingencies, are expensed to cost of sales as revenue from product sales is recognized.
Intangible Assets	Intangible Assets: The Company maintains definite-lived intangible assets related to the Licensor agreement. These assets are amortized over their remaining useful lives, which are estimated based on the shorter of the remaining patent life or the estimated useful life of the underlying product. Intangible assets are amortized using the economic consumption method if anticipated future revenues can be reasonably estimated. The straight-line method is used when future revenues cannot be reasonably estimated. The Company assesses its intangible assets for impairment if indicators are present or changes in circumstance suggest that impairment may exist. Events that could result in an impairment, or trigger an interim impairment assessment, include the receipt of additional clinical or nonclinical data regarding one of the Company’s drug candidates or a potentially competitive drug candidate, changes in the clinical development program for a drug candidate, or new information regarding potential sales for the drug. If impairment indicators are present or changes in circumstance suggest that impairment may exist, the Company performs a recoverability test by comparing the sum of the estimated undiscounted cash flows of each intangible asset to its carrying value on the condensed consolidated balance sheet. If the undiscounted cash flows used in the recoverability test are less than the carrying value, the Company would determine the fair value of the intangible asset and recognize an impairment loss if the carrying value of the intangible asset exceeds its fair value.
Inventory	Inventory: The Company values its inventories at the lower of cost or estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and it writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment is first identified. Such impairment charges, should they occur, are recorded within the cost of sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required, which would be recorded as a cost of sales in the consolidated statements of operations and comprehensive loss. The Company capitalizes inventory costs associated with the Company’s products after regulatory approval, if any, when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized. Inventory acquired prior to receipt of marketing approval of a product candidate is expensed as research and development expense as incurred. Inventory that can be used in either the production of clinical or commercial product is expensed as research and development expense when selected for use in a clinical trial. Starter kits, provided to patients prior to insurance approval, are expensed by the Company to sales and marketing expense as incurred.
Revenue Recognition	Revenue Recognition: The Company adopted Accounting Standards Codification (“ASC”) Topic 606 - Revenue from Contracts with Customers (“Topic 606”) on January 1, 2017. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements, and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of the promised goods or services, in an amount that reflects the consideration which the entity expects to be entitled in exchange for those goods or services. The Company had no contracts with customers until the FDA approved NERLYNX on July 17, 2017. Subsequent to receiving FDA approval, the Company entered into a limited number of arrangements with specialty pharmacies (“SPs”) and specialty distributors (“SDs”) in the U.S. (collectively, its “Customers”) to distribute NERLYNX. These arrangements are the Company’s initial contracts with customers. The Company has determined that these sales channels with customers are similar. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to arrangements that meet the definition of a contract under Topic 606, including when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. For a complete discussion of accounting for product revenue, see Product Revenue, Net Product Revenue, Net: The Company sells NERLYNX to a limited number of SPs and SDs in the U.S. (collectively, its “Customers”). These Customers subsequently resell the Company’s products to patients and certain medical centers or hospitals. In addition to distribution agreements with Customers, the Company enters into arrangements with health care providers and payors that provide for government mandated and/or privately negotiated rebates, chargebacks, and discounts with respect to the purchase of the Company’s products. The Company recognizes revenue on product sales when the Customer obtains control of the Company's product, which occurs at a point in time (upon delivery). Product revenue is recorded net of applicable reserves for variable consideration, including discounts and allowances. The Company’s payment terms range between 10 and 60 days. Shipping and handling costs for product shipments occur prior to the customer obtaining control of the goods, and are recorded in cost of sales. If taxes should be collected from Customers relating to product sales and remitted to governmental authorities, they will be excluded from revenue. The Company expenses incremental costs of obtaining a contract when incurred, if the expected amortization period of the asset that the Company would have recognized is one year or less. However, no such costs were incurred during the three months ended September 30, 2017. Reserves for Variable Consideration: Revenue from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established. Components of variable consideration include trade discounts and allowances, product returns, provider chargebacks and discounts, government rebates, payor rebates, and other incentives, such as voluntary patient assistance, and other allowances that are offered within contracts between the Company and its Customers, payors, and other indirect customers relating to the Company’s sale of its products. These reserves, as detailed below, are based on the amounts earned, or to be claimed on the related sales, and are classified as reductions of accounts receivable (if the amount is payable to the Customer) or a current liability (if the amount is payable to a party other than a Customer). These estimates take into consideration a range of possible outcomes which are probability-weighted in accordance with the expected value method in Topic 606 for relevant factors such as current contractual and statutory requirements, specific known market events and trends, industry data, and forecasted customer buying and payment patterns. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the respective underlying contracts. The amount of variable consideration which is included in the transaction price may be constrained, and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. The Company’s analyses also contemplated application of the constraint in accordance with the guidance, under which it determined a material reversal of revenue would not occur in a future period for the estimates detailed below as of September 30, 2017 and, therefore, the transaction price was not reduced further during the three months ended September 30, 2017. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from the Company’s estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known. Trade Discounts and Allowances: The Company generally provides Customers with discounts which include incentive fees that are explicitly stated in the Company’s contracts and are recorded as a reduction of revenue in the period the related product revenue is recognized. In addition, the Company compensates (through trade discounts and allowances) its Customers for sales order management, data, and distribution services. However, the Company has determined such services received to date are not distinct from the Company’s sale of products to the Customer and, therefore, these payments have been recorded as a reduction of revenue within the statement of operations and comprehensive loss through September 30, 2017, as well as a reduction to trade receivables, net on the condensed consolidated balance sheets. Product Returns: Consistent with industry practice, the Company offers the SPs and SDs limited product return rights for damages and expiring product, provided it is within a specified period around the product expiration date as set forth in the applicable individual distribution agreement. The Company estimates the amount of its product sales that may be returned by its Customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as reductions to trade receivables, net on the condensed consolidated balance sheets. The Company currently estimates product return liabilities using available industry data and its own sales information, including its visibility into the inventory remaining in the distribution channel. The Company has not received any returns to date and believes that returns of its products will be minimal. Provider Chargebacks and Discounts: Chargebacks for fees and discounts to providers represent the estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices charged to Customers who directly purchase the product from the Company. Customers charge the Company for the difference between what they pay for the product and the ultimate selling price to the qualified healthcare providers. These reserves are established in the same period that the related revenue is recognized, resulting in a reduction of product revenue and trade receivables, net. Chargeback amounts are generally determined at the time of resale to the qualified healthcare provider by Customers, and the Company generally issues credits for such amounts within a few weeks of the Customer’s notification to the Company of the resale. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at each reporting period-end that the Company expects will be sold to qualified healthcare providers, and chargebacks that Customers have claimed, but for which the Company has not yet issued a credit. Government Rebates: The Company is subject to discount obligations under state Medicaid programs and Medicare. These reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included in accrued expenses and other current liabilities on the condensed consolidated balance sheets. For Medicare, the Company also estimates the number of patients in the prescription drug coverage gap for whom the Company will owe an additional liability under the Medicare Part D program. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimated future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel inventories at the end of each reporting period. Payor Rebates: The Company contracts with certain private payor organizations, primarily insurance companies and pharmacy benefit managers, for the payment of rebates with respect to utilization of its products. The Company estimates these rebates and records such estimates in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability. Other Incentives: Other incentives which the Company offers include voluntary patient assistance programs, such as the co-pay assistance program, which are intended to provide financial assistance to qualified commercially-insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay assistance is based on an estimate of claims and the cost per claim that the Company expects to receive associated with product that has been recognized as revenue, but remains in the distribution channel inventories at the end of each reporting period. The adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included as a component of accrued expenses and other current liabilities on the condensed consolidated balance sheets.
Assets Measured at Fair Value on a Recurring Basis	Assets Measured at Fair Value on a Recurring Basis: Accounting Standards Codification, or ASC, 820, Fair Value Measurement Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets. Level 3: Valuations derived from valuation techniques in which one or more significant inputs are unobservable. Following are the major categories of assets measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016, using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3) (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds — 26,620 — 26,620 $ 68,911 $ 26,620 $ — $ 95,531 December 31, 2016 Level 1 Level 2 Level 3 Total Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper — 5,998 — 5,998 Marketable securities - corporate bonds — 28,984 — 28,984 $ 188,543 $ 34,982 $ — $ 223,525 The Company’s investments in commercial paper, corporate bonds and U.S. government securities are exposed to price fluctuations. The fair value measurements for commercial paper, corporate bonds and U.S. government securities are based upon the quoted prices of similar items in active markets multiplied by the number of securities owned. The Company invests its excess cash in commercial paper and debt instruments of corporations. As of September 30, 2017, the Company’s short-term investments had a weighted average maturity of less than one year. The following tables summarize the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Estimated September 30, 2017 (in years) cost Gains Losses fair value Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds Less than 1 26,620 — (7 ) 26,613 $ 95,531 $ — $ (7 ) $ 95,524 Maturity Amortized Unrealized Estimated December 31, 2016 (in years) cost Gains Losses fair value Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper Less than 1 5,998 — — 5,998 Marketable securities - corporate bonds Less than 1 28,984 — (13 ) 28,971 $ 223,525 $ — $ (13 ) $ 223,512
Concentration of Risk	Concentration of Risk: Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash and cash equivalents. The Company’s cash and cash equivalents in excess of the Federal Deposit Insurance Corporation and the Securities Investor Protection Corporation insured limits at September 30, 2017, were approximately $85.4 million. The Company does not believe it is exposed to any significant credit risk due to the quality of the financial instruments in which the money is held. Pursuant to the Company’s internal investment policy, investments must be rated A-1/P-1 or better by Standard and Poor’s Corporation and Moody’s Investors Service at the time of purchase.
Property and Equipment	Property and Equipment: Property and equipment are recorded at cost and depreciated over estimated useful lives ranging from three to five years using the straight-line method. Leasehold improvements are recorded at cost and amortized over the shorter of their useful lives or the term of the lease by use of the straight-line method. Maintenance and repair costs are charged to operations as incurred. The Company assesses the impairment of long-lived assets, primarily property and equipment, whenever events or changes in business circumstances indicate that carrying amounts of the assets may not be fully recoverable. When such events occur, management determines whether there has been impairment by comparing the asset’s carrying value with its fair value, as measured by the anticipated undiscounted net cash flows of the asset. Should impairment exist, the asset is written down to its estimated fair value. The Company has not recognized any impairment losses through September 30, 2017.
Research and Development Expenses	Research and Development Expenses: Research and development expenses are charged to operations as incurred. The major components of research and development costs include clinical manufacturing costs, clinical trial expenses, consulting and other third-party costs, salaries and employee benefits, stock-based compensation expense, supplies and materials, and allocations of various overhead costs. Clinical trial expenses include, but are not limited to, investigator fees, site costs, comparator drug costs, and clinical research organization, or CRO, costs. In the normal course of business, the Company contracts with third parties to perform various clinical trial activities in the ongoing development of potential products. The financial terms of these agreements are subject to negotiation and variations from contract to contract and may result in uneven payment flows. Payments under the contracts depend on factors such as the achievement of certain events, the successful enrollment of patients and the completion of portions of the clinical trial or similar conditions. The Company’s accruals for clinical trials are based on estimates of the services received and efforts expended pursuant to contracts with numerous clinical trial sites, cooperative groups and CROs. The objective of the Company’s accrual policy is to record expenses in the unaudited condensed consolidated financial statements as the actual services are performed and efforts expended. As actual costs become known, the Company records the actual expenses in that period. In instances where the Company enters into agreements with third parties for clinical trials and other consulting activities, upfront amounts are recorded to prepaid expenses and other in the accompanying unaudited condensed consolidated balance sheets and expensed as services are performed or as the underlying goods are delivered. If the Company does not expect the services to be rendered or goods to be delivered, any remaining capitalized amounts for non-refundable upfront payments are charged to expense immediately. Amounts due under such arrangements may be either fixed fee or fee for service, and may include upfront payments, monthly payments and payments upon the completion of milestones or receipt of deliverables. Costs related to the acquisition of technology rights and patents for which development work is still in process are charged to operations as incurred and considered a component of research and development costs.
Stock-Based Compensation	Stock-Based Compensation: Stock option awards: ASC 718, Compensation — Stock Compensation Restricted stock units: The restricted stock units, or RSUs,
Net Loss per Common Share	Net Loss per Common Share: Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of common shares outstanding during the periods presented as required by ASC 260, Earnings per Share
Deferred Rent	Deferred Rent: The Company has entered into operating lease agreements for its corporate offices in Los Angeles and South San Francisco that contain provisions for future rent increases, leasehold improvement allowances and rent abatements. The Company records monthly rent expense equal to the total of the payments due over the lease term, divided by the number of months of the lease term. The difference between the rent expense recorded and the amount paid is credited or charged to deferred rent, which is reflected as a separate line item in the accompanying unaudited condensed consolidated balance sheets. Additionally, the Company recorded as deferred rent the cost of the leasehold improvements paid by the landlord, which is amortized on a straight-line basis over the term of the lease.
Issuance of Common Stock Upon Exercise of Stock Option Grants	Issuance of Common Stock Upon Exercise of Stock Option Grants: When a stock option grant is exercised, the Company notifies its transfer agent to release the required number of shares of common stock from the reserve for the Puma Biotechnology, Inc. 2011 Incentive Award Plan, as amended, or the 2011 Plan. The Company records the transaction for the cash received and the issuance of common shares. Should there be a delay in the cash receipts due to the settlement period, the Company records a receivable from the exercise of an option as a reduction of stockholders’ equity on the unaudited condensed consolidated balance sheet.
Recently Issued Accounting Standards	Recently Issued Accounting Standards: In May 2014, the Financial Accounting Standards Board, FASB, issued a new accounting standard that amends the guidance for the recognition of revenue from contracts with customers to transfer goods and services. The FASB has subsequently issued additional, clarifying standards to address issues arising from implementation of the new revenue recognition standard. The new revenue recognition standard and clarifying standards are effective for interim and annual periods beginning on January 1, 2018, but could have been adopted early beginning January 1, 2017. The Company has chosen to adopt this standard in 2017 as it began to generate revenue. The Company has also identified and implemented changes to its accounting policies, business processes, and internal controls to support the new accounting and disclosure requirements. In February 2016, the FASB issued Accounting Standards Update, or ASU, No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation: Improvements to Employee Share-Based Payment Accounting, In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows Topic 230 : Classification of Certain Cash Receipts and Cash Payments a consensus of the Emerging Issues Task Force In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows Topic 230 Restricted Cash In January 2017 Business Combinations (Topic 805): Clarifying the Definition of a Business

Significant Accounting Polici19

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Assets Measured at Fair Value on Recurring Basis	Following are the major categories of assets measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016, using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3) (in thousands): September 30, 2017 Level 1 Level 2 Level 3 Total Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds — 26,620 — 26,620 $ 68,911 $ 26,620 $ — $ 95,531 December 31, 2016 Level 1 Level 2 Level 3 Total Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper — 5,998 — 5,998 Marketable securities - corporate bonds — 28,984 — 28,984 $ 188,543 $ 34,982 $ — $ 223,525
Summary of Short-term Investments	The following tables summarize the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Estimated September 30, 2017 (in years) cost Gains Losses fair value Cash equivalents $ 68,911 $ — $ — $ 68,911 Marketable securities - corporate bonds Less than 1 26,620 — (7 ) 26,613 $ 95,531 $ — $ (7 ) $ 95,524 Maturity Amortized Unrealized Estimated December 31, 2016 (in years) cost Gains Losses fair value Cash equivalents $ 188,543 $ — $ — $ 188,543 Commercial paper Less than 1 5,998 — — 5,998 Marketable securities - corporate bonds Less than 1 28,984 — (13 ) 28,971 $ 223,525 $ — $ (13 ) $ 223,512

Prepaid Expenses and Other (Tab

Prepaid Expenses and Other (Tables)	9 Months Ended
	Sep. 30, 2017
Banking And Thrift [Abstract]
Components of Prepaid Expenses and Other	Prepaid expenses and other consisted of the following (in thousands): September 30, 2017 December 31, 2016 Current: CRO services $ 6,724 $ 3,471 Other clinical development 664 1,069 Insurance 255 1,159 Other 1,638 1,299 9,281 6,998 Long-term: CRO services 1,726 5,077 Other clinical development 565 1,243 Insurance 16 40 Other 1,544 486 3,851 6,846 Totals $ 13,132 $ 13,844

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2017
Property Plant And Equipment [Abstract]
Property and Equipment	Property and equipment consisted of the following (in thousands): Property and Equipment: September 30, 2017 December 31, 2016 Leasehold improvements $ 3,878 $ 3,878 Computer equipment 2,112 1,822 Telephone equipment 296 256 Furniture and fixtures 2,207 2,146 8,493 8,102 Less: accumulated depreciation and amortization (3,779 ) (2,949 ) Totals $ 4,714 $ 5,153

Intangible assets, net (Tables)

Intangible assets, net (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible assets, net	Intangible assets, net consisted of the following (in thousands): September 30, 2017 Estimated useful life Acquired and in-licensed rights $ 50,000 13 Years Less: accumulated amortization (621 ) Total intangible asset, net $ 49,379

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2017
Payables And Accruals [Abstract]
Accrued Expenses	Accrued expenses consisted of the following (in thousands): September 30, 2017 December 31, 2016 Accrued CRO services $ 8,323 $ 6,609 Accrued other clinical development 7,243 7,015 Accrued legal fees 2,806 706 Accrued compensation 8,486 3,058 Accrued in-licensed rights 50,000 — Other 2,750 38 Totals $ 79,608 $ 17,426

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Employee Stock-based Compensation	Employee stock-based compensation for the three and nine months ended September 30, 2017 and 2016 were as follows (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Stock-based compensation: Options - Research and development, or R&D $ 15,825 $ 20,258 $ 54,062 $ 66,376 Selling, general and administrative, or SG&A 5,817 6,802 18,371 18,852 Performance shares - R&D — 68 — 139 Restricted stock units - R&D 2,333 1,754 6,185 1,754 SG&A 2,513 869 4,595 869 Total stock-based compensation expense $ 26,488 $ 29,751 $ 83,213 $ 87,990
Fair Value Options Weighted-Average Assumptions	The fair value of options granted to employees was estimated using the Black-Scholes Option Pricing Method (see Note 2—Significant Accounting Policies) with the following weighted-average assumptions used during the nine months ended September 30, 2017 and 2016: 2017 2016 Dividend yield 0.0 % 0.0 % Expected volatility 70.2 % 67.3 % Risk-free interest rate 2.0 % 1.4 % Expected life in years 5.83 5.72
Activity with Respect to Options Granted	Activity with respect to options granted under the 2011 Plan is summarized as follows: Shares Weighted Average Exercise Price Weighted Contractual Term (years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 6,578,522 $ 87.52 8.0 $ 18,442 Granted 519,791 $ 38.87 Forfeited (272,399 ) $ 50.26 Exercised (419,504 ) $ 46.85 $ 18,366 Expired (111,218 ) $ 117.89 Outstanding at September 30, 2017 6,295,192 $ 87.29 7.4 $ 318,349 Nonvested at September 30, 2017 2,333,232 58.97 8.8 $ 151,369
Stock Options	The weighted-average grant date fair value of options granted during the nine months ended September 30, 2017 and 2016, were $24.30 per share and $26.79 per share, respectively. Weighted Average Grant-Date Stock options Shares Fair Value Nonvested shares at December 31, 2016 3,106,083 $ 47.78 Granted 519,791 24.30 Vested/Issued (1,020,243 ) 61.53 Forfeited (272,399 ) 30.28 Nonvested shares at September 30, 2017 2,333,232 35.31
Restricted Stock Units	Weighted Average Grant-Date Restricted stock units Shares Fair Value Nonvested shares at December 31, 2016 630,508 $ 54.35 Granted 569,750 79.82 Vested/Issued (203,892 ) 54.35 Forfeited (40,306 ) 54.35 Nonvested shares at September 30, 2017 956,060 $ 69.53

Business and Basis of Present25

Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Net loss		$ (77,180)	$ (65,781)	$ (227,877)	$ (203,350)
Net cash used in operating activities				(136,861)	$ (100,729)
Cash and cash equivalents and marketable securities		$ 106,300		$ 106,300
Underwritten Public Offering
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Net proceeds from issuance of common stock	$ 161,900

Significant Accounting Polici26

Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Significant Accounting Policies [Line Items]
Accounts written off			$ 0
Amortization expenses related to intangible assets	$ 600,000
Estimated future amortization expense related to intangible assets, remainder of 2017	1,000,000		1,000,000
Estimated future amortization expense related to intangible assets, 2018	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2019	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2020	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2021	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2022	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2023	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2024	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2025	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2026	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2027	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2028	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2029	3,900,000		3,900,000
Estimated future amortization expense related to intangible assets, 2030	1,000,000		1,000,000
Incremental costs expenses	0		0
Cash and cash equivalents in excess of insured limits	$ 85,400,000		$ 85,400,000
Employee Stock Option
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	6,295,192	5,730,151	6,295,192	5,730,151
Warrants
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	2,116,250	2,116,250	2,116,250	2,116,250
Performance Awards
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share		9,469		9,469
Restricted Stock Units
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	956,060		956,060
Minimum
Significant Accounting Policies [Line Items]
Revenue recognition, payment terms			10 days
Property and equipment, useful lives			3 years
Maximum
Significant Accounting Policies [Line Items]
Revenue recognition, payment terms			60 days
Amortization period recognized	1 year
Weighted average maturity period of short-term investments			1 year
Property and equipment, useful lives			5 years

Assets Measured at Fair Value o

Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 68,911	$ 188,543
Total	95,531	223,525
Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		5,998
Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	26,620	28,984
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	68,911	188,543
Total	68,911	188,543
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	26,620	34,982
Level 2 | Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		5,998
Level 2 | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 26,620	$ 28,984

Summary of Short-term Investmen

Summary of Short-term Investments (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 95,531	$ 223,525
Unrealized Losses	(7)	(13)
Estimated fair value	95,524	223,512
Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	68,911	188,543
Estimated fair value	$ 68,911	$ 188,543
Commercial paper
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		Less than 1
Amortized cost		$ 5,998
Estimated fair value		$ 5,998
Corporate bonds
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	Less than 1	Less than 1
Amortized cost	$ 26,620	$ 28,984
Unrealized Losses	(7)	(13)
Estimated fair value	$ 26,613	$ 28,971

Components of Prepaid Expenses

Components of Prepaid Expenses and Other (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	$ 9,281	$ 6,998
Prepaid expenses and other, long-term	3,851	6,846
Totals	13,132	13,844
CRO services
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	6,724	3,471
Prepaid expenses and other, long-term	1,726	5,077
Other clinical development
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	664	1,069
Prepaid expenses and other, long-term	565	1,243
Insurance
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	255	1,159
Prepaid expenses and other, long-term	16	40
Other
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	1,638	1,299
Prepaid expenses and other, long-term	$ 1,544	$ 486

Property and Equipment (Detail)

Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 8,493	$ 8,102
Less: accumulated depreciation and amortization	(3,779)	(2,949)
Totals	4,714	5,153
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Gross	3,878	3,878
Computer Equipment
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Gross	2,112	1,822
Telephone Equipment
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Gross	296	256
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,207	$ 2,146

Schedule of Intangible assets,

Schedule of Intangible assets, net (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Finite Lived Intangible Assets [Line Items]
Acquired and in-licensed rights	$ 50,000
Less: accumulated amortization	(621)
Total intangible asset, net	$ 49,379
Acquired and in-licensed rights
Finite Lived Intangible Assets [Line Items]
Estimated useful life	13 years

Accrued Expenses (Detail)

Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued CRO services	$ 8,323	$ 6,609
Accrued other clinical development	7,243	7,015
Accrued legal fees	2,806	706
Accrued compensation	8,486	3,058
Accrued in-licensed rights	50,000
Other	2,750	38
Totals	$ 79,608	$ 17,426

Stockholders Equity - Additiona

Stockholders Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Stockholders Equity Note [Line Items]
Share based compensation awarded	519,791
Weighted-average grant date fair value of options granted	$ 24.30	$ 26.79
Non Vested Stock Options
Stockholders Equity Note [Line Items]
Estimated unrecognized employee compensation cost related to non-vested stock options granted	$ 68.7
Estimated unrecognized employee compensation cost related to non-vested stock options granted, Weighted-average period of recognition	1 year 4 months 25 days
Restricted Stock Units
Stockholders Equity Note [Line Items]
Estimated unrecognized employee compensation cost related to non-vested stock options granted	$ 56.3
Estimated unrecognized employee compensation cost related to non-vested stock options granted, Weighted-average period of recognition	2 years 6 months
2011 Plan
Stockholders Equity Note [Line Items]
Common stock shares reserved for issuance	12,529,412
2017 Employment Inducement Incentive Award Plan
Stockholders Equity Note [Line Items]
Common stock shares reserved for issuance	1,000,000
Share based compensation awarded	233,250
2011 and 2017 Plan | Restricted Stock Units
Stockholders Equity Note [Line Items]
Shares vesting period	3 years
Maximum | 2011 Plan
Stockholders Equity Note [Line Items]
Stock options granted, term	10 years
Maximum | 2017 Employment Inducement Incentive Award Plan
Stockholders Equity Note [Line Items]
Stock options granted, term	10 years

Employee Stock-based Compensati

Employee Stock-based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 26,488	$ 29,751	$ 83,213	$ 87,990
Employee Stock Option | Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	15,825	20,258	54,062	66,376
Employee Stock Option | Selling, general and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	5,817	6,802	18,371	18,852
Performance Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense		68		139
Restricted Stock Units | Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	2,333	1,754	6,185	1,754
Restricted Stock Units | Selling, general and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 2,513	$ 869	$ 4,595	$ 869

Fair Value Options Weighted-Ave

Fair Value Options Weighted-Average Assumptions (Detail) - Employee Stock Option	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%
Expected volatility	70.20%	67.30%
Risk-free interest rate	2.00%	1.40%
Expected life in years	5 years 9 months 29 days	5 years 8 months 19 days

Activity with Respect to Option

Activity with Respect to Options Granted (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Shares
Beginning balance, shares	6,578,522
Granted, shares	519,791
Forfeited, shares	(272,399)
Exercised, shares	(419,504)
Expired, shares	(111,218)
Ending balance, shares	6,295,192	6,578,522
Nonvested, shares	2,333,232	3,106,083
Weighted Average Exercise Price
Beginning Balance, Weighted Average Exercise Price	$ 87.52
Granted, Weighted Average Exercise Price	38.87
Forfeited, Weighted Average Exercise Price	50.26
Exercised, Weighted Average Exercise Price	46.85
Expired, Weighted Average Exercise Price	117.89
Ending Balance, Weighted Average Exercise Price	87.29	$ 87.52
Nonvested, Weighted Average Exercise Price	$ 58.97
Weighted Average Remaining Contractual Term (years)
Weighted Average Remaining Contractual Term (years)	7 years 4 months 24 days	8 years
Nonvested, Weighted Average Remaining Contractual Term (years)	8 years 9 months 18 days
Aggregate Intrinsic Value
Shares, Outstanding, Aggregate Intrinsic Value	$ 318,349	$ 18,442
Exercised, Aggregate Intrinsic Value	18,366
Nonvested, Aggregate Intrinsic Value	$ 151,369

Stock Options (Detail)

Stock Options (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Shares
Nonvested shares, Beginning balance	3,106,083
Granted, shares	519,791
Vested/Issued, shares	(1,020,243)
Forfeited, shares	(272,399)
Nonvested shares, Ending balance	2,333,232
Weighted Average Grant-Date Fair Value
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value	$ 47.78
Granted, Weighted Average Grant-Date Fair Value	24.30	$ 26.79
Vested/Issued, Weighted Average Grant-Date Fair Value	61.53
Forfeited, Weighted Average Grant-Date Fair Value	30.28
Nonvested, Ending balance, Weighted Average Grant-Date Fair Value	$ 35.31

Restricted Stock Units (Detail)

Restricted Stock Units (Detail) - Restricted Stock Units	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Shares
Nonvested shares, Beginning balance | shares	630,508
Granted, shares | shares	569,750
Vested/Issued, shares | shares	(203,892)
Forfeited, shares | shares	(40,306)
Nonvested shares, Ending balance | shares	956,060
Weighted Average Grant-Date Fair Value
Nonvested, Beginning balance, Weighted Average Grant-Date Fair Value | $ / shares	$ 54.35
Granted, Weighted Average Grant-Date Fair Value | $ / shares	79.82
Vested/Issued, Weighted Average Grant-Date Fair Value | $ / shares	54.35
Forfeited, Weighted Average Grant-Date Fair Value | $ / shares	54.35
Nonvested, Ending balance, Weighted Average Grant-Date Fair Value | $ / shares	$ 69.53

401(K) Savings Plan - Additiona

401(K) Savings Plan - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution expenses	$ 0.6	$ 0.7
First 3% of each Participant's Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's matching contributions to the 401(k)plan	100.00%
Second 2% of each Participant's Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's matching contributions to the 401(k)plan	50.00%

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Detail)	Apr. 14, 2016DerivativeLawsuit
Commitments And Contingencies Disclosure [Abstract]
Number of shareholders derivative lawsuits	2

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Silicon Valley Bank and Oxford finance - Term Loan	Oct. 31, 2017USD ($)Tranche	Sep. 30, 2017
Subsequent Events
Subsequent Event [Line Items]
Term loan, maximum borrowing capacity	$ 100,000,000
Number of tranches | Tranche	2
First Tranche | Subsequent Events
Subsequent Event [Line Items]
Gross proceeds from credit facility	$ 50,000,000
Line of credit facility closing date	Oct. 31, 2017
Second Tranche
Subsequent Event [Line Items]
Line of credit facility, description		The second tranche of $50.0 million may be drawn at the Company’s option between March 31, 2018 and June 30, 2018 provided the Company has achieved a specified minimum revenue milestone and no event of default is occurring.
Second Tranche | Subsequent Events
Subsequent Event [Line Items]
Line of credit facility available upon achievement of specified minimum revenue milestone	$ 50,000,000
Loan maturity date	Oct. 31, 2022