Halozyme Therapeutics (HALO) 10-K 20 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 13, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	HALOZYME THERAPEUTICS INC.
Trading Symbol	HALO
Entity Central Index Key	1,159,036
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1.3
Entity Common Stock, Shares Outstanding		143,076,590

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 168,740	$ 66,764
Marketable securities, available-for-sale	300,474	138,217
Accounts receivable, net	22,133	15,680
Inventories	5,146	14,623
Prepaid expenses and other assets	13,879	21,248
Total current assets	510,372	256,532
Property and equipment, net	3,520	4,264
Prepaid expenses and other assets	5,553	219
Restricted cash	500	500
Total assets	519,945	261,515
Current liabilities:
Accounts payable	7,948	3,578
Accrued expenses	39,601	28,821
Deferred revenue, current portion	6,568	4,793
Current portion of long-term debt, net	77,211	17,393
Total current liabilities	131,328	54,585
Deferred revenue, net of current portion	54,297	39,825
Long-term debt, net	125,140	199,228
Other long-term liabilities	814	358
Commitments and contingencies (Note 9)
Stockholders' equity (deficit):
Preferred stock - $0.001 par value; 20,000 shares authorized; no shares issued and outstanding	0	0
Common stock - $0.001 par value; 200,000 shares authorized; 142,789 and 129,502 shares issued and outstanding at December 31, 2017 and 2016, respectively	143	130
Additional paid-in capital	731,044	552,737
Accumulated other comprehensive loss	(450)	(6)
Accumulated deficit	(522,371)	(585,342)
Total stockholders' equity (deficit)	208,366	(32,481)
Total liabilities and stockholders' equity (deficit)	$ 519,945	$ 261,515

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	20,000	20,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	142,789	129,502
Common stock, shares outstanding	142,789	129,502

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Product sales, net	$ 50,396	$ 53,392	$ 46,082
Royalties	63,507	50,984	30,975
Revenues under collaborative agreements	202,710	42,315	58,000
Total revenues	316,613	146,691	135,057
Operating expenses:
Cost of product sales	31,152	33,206	29,245
Research and development	150,643	150,842	93,236
Selling, general and administrative	53,816	45,853	40,028
Total operating expenses	235,611	229,901	162,509
Operating income (loss)	81,002	(83,210)	(27,452)
Other income (expense):
Investment and other income, net	2,592	1,326	422
Interest expense	(21,984)	(19,977)	(5,201)
Income (loss) before income taxes	61,610	(101,861)	(32,231)
Income tax (benefit) expense	(1,361)	1,162	0
Net income (loss)	$ 62,971	$ (103,023)	$ (32,231)
Net income (loss) per share, Basic	$ 0.46	$ (0.81)	$ (0.25)
Net income (loss) per share, Diluted	$ 0.45	$ (0.81)	$ (0.25)
Shares used in computing basic net income (loss) per share	136,419	127,964	126,704
Shares used in computing diluted net income (loss) per share	139,068	127,964	126,704

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 62,971	$ (103,023)	$ (32,231)
Other comprehensive income (loss):
Unrealized (loss) gain on marketable securities	(430)	93	(58)
Foreign currency translation adjustment	(14)	0	0
Total comprehensive income (loss)	$ 62,527	$ (102,930)	$ (32,289)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net income (loss)	$ 62,971	$ (103,023)	$ (32,231)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Share-based compensation	30,670	25,585	20,838
Depreciation and amortization	2,161	2,410	1,677
Non-cash interest expense	1,761	2,896	1,243
Payment-in-kind Interest expense on long-term debt	0	13,184	879
(Accretion of discounts) amortization of premiums on marketable securities, net	(303)	552	0
Loss on disposal of equipment	46	8	8
Deferral of unearned revenue	22,759	701	4,379
Recognition of deferred revenue	(6,512)	(9,304)	(5,789)
Deferral of rent expense	13	0	441
Recognition of deferred rent	(185)	(370)	(276)
Other	(16)	0	0
Changes in operating assets and liabilities:
Accounts receivable, net	(6,453)	16,730	(23,261)
Inventories	9,477	(5,134)	(3,083)
Prepaid expenses and other assets	2,035	5,626	(15,774)
Accounts payable and accrued expenses	15,629	(244)	13,866
Net cash provided by (used in) operating activities	134,053	(50,383)	(37,083)
Investing activities:
Purchases of marketable securities	(398,187)	(155,412)	(71,482)
Proceeds from maturities of marketable securities	235,805	81,783	79,730
Purchases of property and equipment	(1,350)	(3,137)	(2,360)
Net cash (used in) provided by investing activities	(163,732)	(76,766)	5,888
Financing activities:
Proceeds from issuance of common stock, net	134,874	0	0
Proceeds from issuance of long-term debt, net	0	203,006	0
Repayment of long-term debt	(15,995)	(54,250)	0
Proceeds from issuance of common stock under equity incentive plans, net of taxes paid related to net share settlement	12,776	1,865	13,098
Net cash provided by financing activities	131,655	150,621	13,098
Net increase (decrease) in cash, cash equivalents and restricted cash	101,976	23,472	(18,097)
Cash, cash equivalents and restricted cash beginning of period	67,264	43,792	61,889
Cash, cash equivalents and restricted cash end of period	169,240	67,264	43,792
Interest Paid	20,295	3,886	3,775
Income Taxes Paid	3,015	1,441	0
Amounts accrued for purchases of property and equipment	$ 189	$ 75	$ 473

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]
Shares outstanding at Dec. 31, 2014		125,721
Total stockholders' equity (deficit) at Dec. 31, 2014	$ 41,352	$ 126	$ 491,694	$ (41)	$ (450,427)
Share-based Compensation	20,838		20,838
Issuance of common stock pursuant to exercise of stock options and vesting of restricted stock units and performance restricted stock units, net		2,056
Value, Stock Options Exercised	13,098	$ 2	13,096
Shares, Restricted Stock Award		375
Value, Restricted Stock Award	0	$ 0	0
Other Comprehensive Income (Loss)	(58)			(58)
Net income (loss)	(32,231)
Shares outstanding at Dec. 31, 2015		128,152
Total stockholders' equity (deficit) at Dec. 31, 2015	42,999	$ 128	525,628	(99)	(482,658)
Adjustment to beginning retained earnings	0		(339)		339
Share-based Compensation	25,585		25,585
Issuance of common stock pursuant to exercise of stock options and vesting of restricted stock units and performance restricted stock units, net		570
Value, Stock Options Exercised	1,948	$ 1	1,947
Shares, Restricted Stock Award		780
Value, Restricted Stock Award	(83)	$ 1	(84)
Other Comprehensive Income (Loss)	93			93
Net income (loss)	(103,023)
Shares outstanding at Dec. 31, 2016		129,502
Total stockholders' equity (deficit) at Dec. 31, 2016	(32,481)	$ 130	552,737	(6)	(585,342)
Share-based Compensation	$ 30,670		30,670
Shares, New Issues	11,500	11,500
Value, New Issues	$ 134,874	$ 11	134,863
Issuance of common stock pursuant to exercise of stock options and vesting of restricted stock units and performance restricted stock units, net		1,796
Value, Stock Options Exercised	12,776	$ 2	12,774
Shares, Restricted Stock Award		(9)
Value, Restricted Stock Award	0	$ 0	0
Other Comprehensive Income (Loss)	(444)			(444)
Net income (loss)	62,971
Shares outstanding at Dec. 31, 2017		142,789
Total stockholders' equity (deficit) at Dec. 31, 2017	$ 208,366	$ 143	$ 731,044	$ (450)	$ (522,371)

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	Organization and Business Halozyme Therapeutics, Inc. is a biotechnology company focused on developing and commercializing novel oncology therapies. We are seeking to translate our unique knowledge of the tumor microenvironment to create therapies that have the potential to improve cancer patient survival. Our research primarily focuses on human enzymes that alter the extracellular matrix and tumor microenvironment. The extracellular matrix is a complex matrix of proteins and carbohydrates surrounding the cell that provides structural support in tissues and orchestrates many important biological activities, including cell migration, signaling and survival. Over many years, we have developed unique technology and scientific expertise enabling us to pursue this target-rich environment for the development of therapies. Our proprietary enzymes are used to facilitate the delivery of injected drugs and fluids, potentially enhancing the efficacy and the convenience of other drugs or can be used to alter tissue structures for potential clinical benefit. We exploit our technology and expertise using a two pillar strategy that we believe enables us to manage risk and cost by: (1) developing our own proprietary products in therapeutic areas with significant unmet medical needs, with a focus on oncology, and (2) licensing our technology to biopharmaceutical companies to collaboratively develop products that combine our technology with the collaborators’ proprietary compounds. The majority of our approved product and product candidates are based on rHuPH20, our patented recombinant human hyaluronidase enzyme. rHuPH20 is the active ingredient in our first commercially approved product, Hylenex ® recombinant, and it works by temporarily breaking down hyaluronan (or “HA”), a naturally occurring complex carbohydrate that is a major component of the extracellular matrix in tissues throughout the body such as skin and cartilage. We believe this temporary degradation creates an opportunistic window for the improved subcutaneous delivery of injectable biologics, such as monoclonal antibodies and other large therapeutic molecules, as well as small molecules and fluids. We refer to the application of rHuPH20 to facilitate the delivery of other drugs or fluids as our ENHANZE ® Technology. We license the ENHANZE Technology to form collaborations with biopharmaceutical companies that develop or market drugs requiring or benefiting from injection via the subcutaneous route of administration. We currently have ENHANZE collaborations with F. Hoffmann-La Roche, Ltd. and Hoffmann-La Roche, Inc. (“Roche”), Baxalta US Inc. and Baxalta GmbH (Baxalta Incorporated was acquired by Shire plc in June 2016) (“Baxalta”), Pfizer Inc. (“Pfizer”), Janssen Biotech, Inc. (“Janssen”), AbbVie, Inc. (“AbbVie”), Eli Lilly and Company (“Lilly”), Bristol-Myers Squibb Company (“BMS”) and Alexion Pharma Holding (“Alexion”).We receive royalties from two of these collaborations, including royalties from sales of one product from the Baxalta collaboration and two products from the Roche collaboration. Future potential revenues from the sales and/or royalties of our approved products, product candidates, and ENHANZE collaborations will depend on the ability of Halozyme and our collaborators to develop, manufacture, secure and maintain regulatory approvals for approved products and product candidates and commercialize product candidates. Our proprietary development pipeline consists primarily of pre-clinical and clinical stage product candidates in oncology. Our lead oncology program is Pegvorhyaluronidase alfa (“PEGPH20”, PEGylated recombinant human hyaluronidase), a molecular entity we are developing in combination with currently approved cancer therapies as a candidate for the systemic treatment of tumors that accumulate HA. We have demonstrated that when HA accumulates in a tumor, it can cause higher pressure in the tumor, reducing blood flow into the tumor and with that, reduced access of cancer therapies to the tumor. PEGPH20 has been demonstrated in animal models to work by temporarily degrading HA surrounding cancer cells resulting in reduced pressure and increased blood flow to the tumor thereby enabling increased amounts of anticancer treatments administered concomitantly gaining access to the tumor. Through our efforts and efforts of our partners and collaborators, we are currently in Phase 3 clinical testing for PEGPH20 with ABRAXANE ® (nab-paclitaxel) and gemcitabine in stage IV pancreatic ductal adenocarcinoma (“PDA”) (HALO 109-301), in Phase 1b clinical testing for PEGPH20 with KEYTRUDA ® (pembrolizumab) in non-small cell lung cancer and gastric cancer (HALO 107-101), in Phase 1b/2 clinical testing for PEGPH20 with HALAVEN ® (eribulin) in patients treated with up to two lines of prior therapy for HER2-negative metastatic breast cancer, in Phase 1b/2 clinical testing for PEGPH20 with Tecentriq® (atezolizumab) in patients with previously treated metastatic PDA, in Phase 1b/2 clinical testing for PEGPH20 with Tecentriq in patients with gastric cancer and in Phase 1b/2 clinical testing for PEGPH20 with Tecentriq in patients with cholangiocarcinoma and gall bladder cancer (HALO 110-101/MATRIX). Except where specifically noted or the context otherwise requires, references to “Halozyme,” “the Company,” “we,” “our,” and “us” in these notes to condensed consolidated financial statements refer to Halozyme Therapeutics, Inc. and its wholly owned subsidiary, Halozyme, Inc., and Halozyme, Inc.’s wholly owned subsidiaries, Halozyme Holdings Ltd., Halozyme Royalty LLC, Halozyme Switzerland GmbH and Halozyme Switzerland Holdings GmbH.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of Halozyme Therapeutics, Inc. and our wholly owned subsidiary, Halozyme, Inc., and Halozyme, Inc.’s wholly owned subsidiaries, Halozyme Holdings Ltd., Halozyme Royalty LLC, Halozyme Switzerland GmbH and Halozyme Switzerland Holdings GmbH. All intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in our consolidated financial statements and accompanying notes. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates. Cash Equivalents and Marketable Securities Cash equivalents consist of highly liquid investments, readily convertible to cash, that mature within ninety days or less from the date of purchase. As of December 31, 2017 , our cash equivalents consisted of money market funds and commercial paper. Marketable securities are investments with original maturities of more than ninety days from the date of purchase that are specifically identified to fund current operations. Marketable securities are considered available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date which reflects management’s intention to use the proceeds from the sale of these investments to fund our operations, as necessary. Such available-for-sale investments are carried at fair value with unrealized gains and losses recorded in other comprehensive gain (loss) and included as a separate component of stockholders’ equity (deficit). The cost of marketable securities is adjusted for amortization of premiums or accretion of discounts to maturity, and such amortization or accretion is included in investment and other income, net in the condensed consolidated statements of operations. We use the specific identification method for calculating realized gains and losses on marketable securities sold. Realized gains and losses and declines in value judged to be other-than-temporary on marketable securities, if any, are included in investment and other income, net in the consolidated statements of operations. Restricted Cash Under the terms of the leases of our facilities, we are required to maintain letters of credit as security deposits during the terms of such leases. At December 31, 2017 and 2016 , restricted cash of $0.5 million was pledged as collateral for the letters of credit. Fair Value of Financial Instruments The authoritative guidance for fair value measurements establishes a three tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, available-for-sale marketable securities, accounts receivable, prepaid expenses and other assets, accounts payable, accrued expenses and long-term debt. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The carrying amount of cash equivalents, accounts receivable, prepaid expenses and other assets, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on Level 3 inputs and the borrowing rates currently available for loans with similar terms, we believe the fair value of long-term debt approximates its carrying value. Available-for-sale marketable securities consist of corporate debt securities, U.S. Treasury securities and commercial paper, and are measured at fair value using Level 1 and Level 2 inputs. Level 2 financial instruments are valued using market prices on less active markets and proprietary pricing valuation models with observable inputs, including interest rates, yield curves, maturity dates, issue dates, settlement dates, reported trades, broker-dealer quotes, issue spreads, benchmark securities or other market related data. We obtain the fair value of Level 2 investments from our investment manager, who obtains these fair values from a third-party pricing source. We validate the fair values of Level 2 financial instruments provided by our investment manager by comparing these fair values to a third-party pricing source. Concentrations of Credit Risk, Sources of Supply and Significant Customers We are subject to credit risk from our portfolio of cash equivalents and marketable securities. These investments were made in accordance with our investment policy which specifies the categories, allocations, and ratings of securities we may consider for investment. The primary objective of our investment activities is to preserve principal while at the same time maximizing the income we receive without significantly increasing risk. We maintain our cash and cash equivalent balances with one major commercial bank and marketable securities with another financial institution. Deposits held with the financial institutions exceed the amount of insurance provided on such deposits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash, cash equivalents and marketable securities to the extent recorded on the consolidated balance sheets. We are also subject to credit risk from our accounts receivable related to our product sales and revenues under our license and collaborative agreements. We have license and collaborative agreements with pharmaceutical companies under which we receive payments for license fees, milestone payments for specific achievements designated in the collaborative agreements, reimbursements of research and development services and supply of bulk formulation of rHuPH20. In addition, we sell Hylenex ® recombinant in the United States to a limited number of established wholesale distributors in the pharmaceutical industry. Credit is extended based on an evaluation of the customer’s financial condition, and collateral is not required. Management monitors our exposure to accounts receivable by periodically evaluating the collectibility of the accounts receivable based on a variety of factors including the length of time the receivables are past due, the financial health of the customer and historical experience. Based upon the review of these factors, we recorded no allowance for doubtful accounts at December 31, 2017 and 2016 . Approximately 86% of the accounts receivable balance at December 31, 2017 represents amounts due from Roche and Baxalta. Approximately 81% of the accounts receivable balance at December 31, 2016 represents amounts due from Roche and Baxalta. The following table indicates the percentage of total revenues in excess of 10% with any single customer: Year Ended December 31, 2017 2016 2015 Roche 38% 63% 42% BMS 32% — — Alexion 13% — — Baxalta 7% 12% 7% Lilly — 6% 19% AbbVie — 4% 17% We attribute revenues under collaborative agreements, including royalties, to the individual countries where the collaborator is headquartered. We attribute revenues from product sales to the individual countries to which the product is shipped. Worldwide revenues from external customers are summarized by geographic location in the following table (in thousands): Year Ended December 31, 2017 2016 2015 United States $ 196,274 $ 52,292 $ 77,149 Switzerland 119,136 93,067 57,136 All other foreign 1,203 1,332 772 Total revenues $ 316,613 $ 146,691 $ 135,057 As of December 31, 2017 and 2016 , we had less than $0.1 million of research equipment in Germany. We rely on two third-party manufacturers for the supply of bulk rHuPH20 for use in the manufacture of Hylenex recombinant and our other collaboration products and product candidates. Payments due to these suppliers represented 4% and 13% of the accounts payable balance at December 31, 2017 and 2016 , respectively. We also rely on a third-party manufacturer for the fill and finish of Hylenex recombinant product under a contract. Payments due to this supplier represented 1% and 2% of the accounts payable balance at December 31, 2017 and 2016 , respectively. Accounts Receivable, Net Accounts receivable is recorded at the invoiced amount and is non-interest bearing. Accounts receivable is recorded net of allowances for doubtful accounts, cash discounts for prompt payment, distribution fees and chargebacks. We recorded no allowance for doubtful accounts at December 31, 2017 and 2016 as the collectibility of accounts receivable was reasonably assured. Inventories Inventories are stated at lower of cost or net realizable value. Cost is determined on a first-in, first-out basis. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. Inventories are reviewed periodically for potential excess, dated or obsolete status. We evaluate the carrying value of inventories on a regular basis, taking into account such factors as historical and anticipated future sales compared to quantities on hand, the price we expect to obtain for products in their respective markets compared with historical cost and the remaining shelf life of goods on hand. Prior to receiving marketing approval from the U.S. Food and Drug Administration (“FDA”) or comparable regulatory agencies in foreign countries, costs related to purchases of bulk rHuPH20 and raw materials and the manufacturing of the product candidates are recorded as research and development expense. All direct manufacturing costs incurred after receiving marketing approval are capitalized as inventory. Inventories used in clinical trials are expensed at the time the inventories are packaged for the clinical trials. As of December 31, 2017 and 2016 , inventories consisted of $2.9 million and $2.3 million , respectively, of Hylenex recombinant inventory, net, and $2.2 million and $12.3 million , respectively, of bulk rHuPH20 for use in the manufacture of Baxalta’s and Roche’s collaboration products. Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization. Equipment is depreciated using the straight-line method over its estimated useful life of three years and leasehold improvements are amortized using the straight-line method over the estimated useful life of the asset or the lease term, whichever is shorter. Impairment of Long-Lived Assets We account for long-lived assets in accordance with authoritative guidance for impairment or disposal of long-lived assets. Long-lived assets are reviewed for events or changes in circumstances, which indicate that their carrying value may not be recoverable. For the years ended December 31, 2017 and 2016 , there was no impairment of the value of long-lived assets. Deferred Rent Rent expense is recorded on a straight-line basis over the initial term of the lease. The difference between rent expense accrued and amounts paid under lease agreements is recorded as deferred rent and is included in accrued expenses and other long-term liabilities, as applicable, in the accompanying consolidated balance sheets. Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity during the period from transactions and other events and circumstances from non-owner sources. Revenue Recognition We generate revenues from product sales and payments received under collaborative agreements. Collaborative agreement payments may include nonrefundable fees at the inception of the agreements, license fees, milestone and event-based payments for specific achievements designated in the collaborative agreements, reimbursements of research and development services and supply of bulk rHuPH20, and/or royalties on sales of products resulting from collaborative arrangements. We recognize revenues in accordance with the authoritative guidance for revenue recognition. We recognize revenue when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the seller’s price to the buyer is fixed or determinable; and (4) collectibility is reasonably assured. Product Sales, Net Hylenex Recombinant We sell Hylenex recombinant in the U.S. to wholesale pharmaceutical distributors, who sell the product to hospitals and other end-user customers. Sales to wholesalers provide for selling prices that are fixed on the date of sale, although we offer discounts to certain group purchasing organizations (“GPOs”), hospitals and government programs. The wholesalers take title to the product, bear the risk of loss of ownership and have economic substance to the inventory. Further, we have no significant obligations for future performance to generate pull-through sales. We have developed sufficient historical experience and data to reasonably estimate future returns and chargebacks of Hylenex recombinant. As a result, we recognize Hylenex recombinant product sales and related cost of product sales at the time title transfers to the wholesalers. Upon recognition of revenue from product sales of Hylenex recombinant, we record certain sales reserves and allowances as a reduction to gross revenue. These reserves and allowances include amounts for product returns (based primarily on an analysis of historical return patterns), distribution fees, prompt payment discounts, and GPO fees and other discounts and fees. We recognize product sales reserves and allowances as a reduction of product sales in the same period the related revenue is recognized. Because of the shelf life of Hylenex recombinant and our lengthy return period, there may be a significant period of time between when the product is shipped and when we issue credits on returned product. If actual product return results differ from our estimates, we will be required to make adjustments to these allowances in the future, which could have an effect on product sales revenue and earnings in the period of adjustments. Bulk rHuPH20 Subsequent to receiving marketing approval from the FDA or comparable regulatory agencies in foreign countries, sales of bulk rHuPH20 for use in collaboration commercial products are recognized as product sales when the materials have met all the specifications required for the customer’s acceptance and title and risk of loss have transferred to the customer. Following the receipt of European marketing approvals of Roche’s Herceptin SC product in August 2013 and MabThera ® SC product in March 2014 and Baxalta’s HYQVIA product in May 2013, revenue from the sales of bulk rHuPH20 for these collaboration products has been recognized as product sales. Revenues under Collaborative Agreements We have entered into license and collaboration agreements under which our collaborators obtained worldwide rights for the use of our proprietary rHuPH20 enzyme in the development and commercialization of their biologic compounds identified as targets. These agreements may also contain other elements. Pursuant to the terms of these agreements, collaborators could be required to make various payments to us for each target, including nonrefundable upfront license fees, exclusivity fees, payments based on achievement of specified milestones designated in the collaborative agreements, annual maintenance fees, reimbursements of research and development services, payments for supply of bulk rHuPH20 used by the collaborator and/or royalties on sales of products resulting from collaborative agreements. In order to account for the multiple-element arrangements, we identify the deliverables included within the collaborative agreement and evaluate which deliverables represent units of accounting. We then determine the appropriate method of revenue recognition for each unit based on the nature and timing of the delivery process. Analyzing the arrangement to identify deliverables requires the use of judgment, and each deliverable may be an obligation to deliver services, a right or license to use an asset, or another performance obligation. The deliverables under our collaborative agreements include (i) the license to our rHuPH20 technology, (ii) at the collaborator’s request, research and development services which are reimbursed at contractually determined rates, and (iii) at the collaborator’s request, supply of bulk rHuPH20 which is reimbursed at our cost plus a margin. A delivered item is considered a separate unit of accounting when the delivered item has value to the collaborator on a standalone basis based on the consideration of the relevant facts and circumstances for each arrangement. We base this determination on the collaborators’ ability to use the delivered items on their own without us supplying undelivered items, which we determine taking into consideration factors such as the research capabilities of the collaborator, the availability of research expertise in this field in the general marketplace, and the ability to procure the supply of bulk rHuPH20 from the marketplace. Arrangement consideration is allocated at the inception of the agreement to all identified units of accounting based on their relative selling price. The relative selling price for each deliverable is determined using vendor specific objective evidence (“VSOE”) of selling price or third-party evidence of selling price if VSOE does not exist. If neither VSOE nor third-party evidence of selling price exists, we use our best estimate of the selling price for the deliverable. The amount of allocable arrangement consideration is limited to amounts that are not contingent upon the delivery of additional items or meeting other specified performance conditions. The consideration received is allocated among the separate units of accounting and the applicable revenue recognition criteria are applied to each of the separate units. Changes in the allocation of the sales price between delivered and undelivered elements can impact revenue recognition but do not change the total revenue recognized under any agreement. Nonrefundable upfront license fees are recognized upon delivery of the license if facts and circumstances dictate that the license has standalone value from the undelivered items, which generally include research and development services and the manufacture of bulk rHuPH20, the relative selling price allocation of the license is equal to or exceeds the upfront license fee, persuasive evidence of an arrangement exists, our price to the collaborator is fixed or determinable and collectibility is reasonably assured. Upfront license fees are deferred if facts and circumstances dictate that the license does not have standalone value. The determination of the length of the period over which to defer revenue is subject to judgment and estimation and can have an impact on the amount of revenue recognized in a given period. When collaborators have rights to elect additional targets, the rights are assessed as to whether they represent deliverables at the inception of the arrangement. In assessing these contingent deliverables, we consider whether the right is a substantive option. We consider a right to be a substantive option if the election of the additional targets is not essential to the functionality of the other elements in the arrangement and if we are truly at risk of the right being exercised. If the right is determined to be a substantive option, we further consider whether the right is priced at a significant and incremental discount that should be accounted for as an element of the arrangement. If a right is determined to be a substantive option and is not priced at a significant and incremental discount, it is not treated as a deliverable in the arrangement and receives no allocation at the inception of the arrangement of the original arrangement consideration. The right is then accounted for when and if it is exercised. When collaborators have a right to return targets, the right is assessed as to whether the target may be returned for a refund of the purchase price, for a credit applied to amounts owed, or in exchange for other dissimilar products. We also assess if we have sufficient history to estimate the likelihood of return. If a right of return is considered to exist and we determine there is not sufficient history to estimate the likelihood of return, the consideration allocated to returnable targets is recorded as deferred revenue on the consolidated balance sheet until the right of return is exercised or expires. Certain of our collaborative agreements provide for milestone payments upon achievement of development and regulatory events and/or specified sales volumes of commercialized products by the collaborator. We account for milestone payments in accordance with the provisions of ASU No. 2010-17, Revenue Recognition - Milestone Method (“Milestone Method of Accounting”). We recognize consideration that is contingent upon the achievement of a milestone in its entirety as revenue in the period in which the milestone is achieved only if the milestone is substantive in its entirety. A milestone is considered substantive when it meets all of the following criteria: 1. The consideration is commensurate with either the entity’s performance to achieve the milestone or the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the entity’s performance to achieve the milestone; 2. The consideration relates solely to past performance; and 3. The consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. A milestone is defined as an event (i) that can only be achieved based in whole or in part on either the entity’s performance or on the occurrence of a specific outcome resulting from the entity’s performance, (ii) for which there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved, and (iii) that would result in additional payments being due to the vendor. Reimbursements of research and development services are recognized as revenue during the period in which the services are performed as long as there is persuasive evidence of an arrangement, the fee is fixed or determinable and collection of the related receivable is reasonably assured. Revenue from the manufacture of bulk rHuPH20 is recognized when the materials have met all specifications required for the collaborator’s acceptance and title and risk of loss have transferred to the collaborator. We do not directly control when any collaborator will request research and development services or supply of bulk rHuPH20; therefore, we cannot predict when we will recognize revenues in connection with research and development services and supply of bulk rHuPH20. Since we receive royalty reports 60 days after quarter end, royalty revenue from sales of collaboration products by our collaborators is recognized in the quarter following the quarter in which the corresponding sales occurred. The collaborative agreements typically provide the collaborators the right to terminate such agreement in whole or on a product-by-product or target-by-target basis at any time upon 30 to 90 days prior written notice to us. There are no performance, cancellation, termination or refund provisions in any of our collaborative agreements that contain material financial consequences to us. Refer to Note 4, Collaborative Agreements , for further discussion on our collaborative arrangements. Cost of Product Sales Cost of product sales consists primarily of raw materials, third-party manufacturing costs, fill and finish costs, freight costs, internal costs and manufacturing overhead associated with the production of Hylenex recombinant and bulk rHuPH20 for use in approved collaboration products. Cost of product sales also consists of the write-down of excess, dated and obsolete inventories and the write-off of inventories that do not meet certain product specifications, if any. Research and Development Expenses Research and development expenses include salaries and benefits, facilities and other overhead expenses, external clinical trial expenses, research related manufacturing services, contract services and other outside expenses. Research and development expenses are charged to operating expenses as incurred when these expenditures relate to our research and development efforts and have no alternative future uses. After receiving approval from the FDA or comparable regulatory agencies in foreign countries for a product, costs related to purchases and manufacturing of bulk rHuPH20 for such product are capitalized as inventory. The manufacturing costs of bulk rHuPH20 for the collaboration products, Herceptin SC, MabThera SC (RITUXAN HYCELA™ in the U.S.) and HYQVIA, incurred after the receipt of marketing approvals are capitalized as inventory. We are obligated to make upfront payments upon execution of certain research and development agreements. Advance payments, including nonrefundable amounts, for goods or services that will be used or rendered for future research and development activities are deferred. Such amounts are recognized as expense as the related goods are delivered or the related services are performed or such time when we do not expect the goods to be delivered or services to be performed. Milestone payments that we make in connection with in-licensed technology for a particular research and development project that have no alternative future uses (in other research and development projects or otherwise) and therefore no separate economic value are expensed as research and development costs at the time the costs are incurred. We currently have no in-licensed technologies that have alternative future uses in research and development projects or otherwise. Clinical Trial Expenses We make payments in connection with our clinical trials under contracts with contract research organizations that support conducting and managing clinical trials. The financial terms of these agreements are subject to negotiation and vary from contract to contract and may result in uneven payment flows. Generally, these agreements set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. A portion of our obligation to make payments under these contracts depends on factors such as the successful enrollment or treatment of patients or the completion of other clinical trial milestones. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly on a prospective basis. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain. Share-Based Compensation We record compensation expense associated with stock options, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and RSUs with performance conditions (“PRSUs”) in accordance with the authoritative guidance for stock-based compensation. The cost of employee services received in exchange for an award of an equity instrument is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense on a straight-line basis over the requisite service period of the award. Share-based compensation expense for an award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized and any previously recognized compensation expense is reversed. Forfeitures are recognized as a reduction of share-based compensation expense as they occur. Income Taxes We provide for income taxes using the liability method. Under this method, deferred income tax assets and liabilities are determined based on the differences between the financial statement carrying amounts of existing assets and liabilities at each year end and their respective tax bases and are measured using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Significant judgment is required by management to determine our provision for income taxes, our deferred tax assets and liabilities, and the valuation allowance to record against our net deferred tax assets, which are based on complex and evolving tax regulations throughout the world. Deferred tax assets and other tax benefits are recorded when it is more likely than not that the position will be sustained upon audit. While we have begun to utilize certain of our net operating losses, we have not yet established a track record of profitability. Accordingly, valuation allowances have been recorded to reduce our net deferred tax assets to zero , with the exception of the alternative minimum tax ("AMT") credit carryover. Under the Tax Cuts and Jobs Act enacted in December 2017, the AMT credit carryover will either be utilized, or if unutilized fully refunded in 2022. For all other deferred tax assets the valuation allowance will reduce the net value to zero until such time as we can demonstrate an ability to realize them. Net Income (Loss) Per Share Basic net income (loss) per common share is computed by dividing net income (loss) for the period by the weighted average number of common shares outstanding during the period, without consideration for common stock equivalents. Outstanding stock options, unvested RSAs, unvested RSUs and unvested PRSUs are considered common stock equivalents and are only included in the calculation of diluted earnings per common share when net income is reported and their effect is dilutive. For the years ended December 31, 2017, 2016 and 2015 , approximately 7.1 million , 13.8 million , and 9.8 million shares, respectively, of outstanding stock options, unvested RSAs, unvested RSUs and unvested PRSUs were excluded from the calculation of diluted net income (loss) per common share because their effect was anti-dilutive. A reconciliation of the numerators and the denominators of the basic and diluted net income (loss) per common share computations is as follows (in thousands, except per share amounts): Year Ended December 31, 2017 2016 2015 Numerator: Net income (loss) $ 62,971 $ (103,023 ) $ (32,231 ) Denominator: Weighted average common shares outstanding for basic 136,419 127,964 126,704 Net effect of dilutive common stock equivalents 2,649 — — Weighted average common shares outstanding for diluted 139,068 127,964 126,704 Net income (loss) per share: Basic $ 0.46 $ (0.81 ) $ (0.25 ) Diluted $ 0.45 $ (0.81 ) $ (0.25 ) Segment Information We operate our business in one segment, which includes all activities related to the research, development and commercialization of our proprietary enzymes. This segment also includes revenues and expenses related to (i) research and development and bulk rHuPH20 manufacturing activities conducted under our collaborative agreements with third parties and (ii) product sales of Hylenex recombinant. The chief operating decision-maker reviews the operating results on an aggregate basis and manages the operations as a single operatin

Fair Value Measurement (Notes)

Fair Value Measurement (Notes)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	Fair Value Measurement Available-for-sale marketable securities consisted of the following (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate debt securities $ 117,427 $ — $ (235 ) $ 117,192 U.S. Treasury securities 66,601 — (201 ) 66,400 Commercial paper 116,882 — — 116,882 $ 300,910 $ — $ (436 ) $ 300,474 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate debt securities $ 40,221 $ 1 $ (15 ) $ 40,207 U.S. Treasury securities 94,002 24 (16 ) 94,010 Commercial paper 4,000 — — 4,000 $ 138,223 $ 25 $ (31 ) $ 138,217 As of December 31, 2017 , 28 available-for-sale marketable securities with a fair market value of $183.6 million were in a gross unrealized loss position of $0.4 million , all of which had been in such position for less than 12 months. Based on our review of these marketable securities, we believe we had no other-than-temporary impairments on these securities as of December 31, 2017 , because we do not intend to sell these securities and it is not more-likely-than-not that we will be required to sell these securities before the recovery of their amortized cost basis. Contractual maturities of available-for-sale debt securities are as follows (in thousands): December 31, 2017 December 31, 2016 Estimated Fair Value Due within one year $ 213,426 $ 132,221 After one but within five years 87,048 5,996 $ 300,474 $ 138,217 The following table summarizes, by major security type, our cash equivalents and available-for-sale marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands): December 31, 2017 December 31, 2016 Level 1 Level 2 Total estimated fair value Level 1 Level 2 Total estimated fair value Cash equivalents: Money market funds $ 142,091 $ — $ 142,091 $ 60,916 $ — $ 60,916 Commercial paper — 15,700 15,700 — — — Available-for-sale marketable securities: Corporate debt securities — 117,192 117,192 — 40,207 40,207 U.S. Treasury securities 66,400 — 66,400 94,010 — 94,010 Commercial paper — 116,882 116,882 — 4,000 4,000 $ 208,491 $ 249,774 $ 458,265 $ 154,926 $ 44,207 $ 199,133 There were no transfers between Level 1 and Level 2 of the fair value hierarchy during the year ended December 31, 2017 . We had no instruments that were classified within Level 3 as of December 31, 2017 and 2016 .

Collaborative Agreements (Notes

Collaborative Agreements (Notes)	12 Months Ended
	Dec. 31, 2017
Deferred Revenue Disclosure [Abstract]
Collaborative Agreements	Collaborative Agreements Roche Collaboration In December 2006, we and Roche entered into a collaboration and license agreement, under which Roche obtained a worldwide license to develop and commercialize product combinations of rHuPH20 and up to thirteen Roche target compounds (the “Roche Collaboration”). Roche initially had the exclusive right to apply rHuPH20 to three pre-defined Roche biologic targets with the option to develop and commercialize rHuPH20 with ten additional targets. Roche had the right to exercise this option to identify additional targets for ten years. As of the ten year anniversary in December 2016, Roche had elected a total of eight targets, two of which are exclusive. In August 2013, Roche received European marketing approval for its collaboration product, Herceptin SC, for the treatment of patients with HER2-positive breast cancer and launched Herceptin SC in the European Union (“EU”) in September 2013. In March 2014, Roche received European marketing approval for its collaboration product, MabThera SC, for the treatment of patients with common forms of non-Hodgkin lymphoma (“NHL”). In June 2014, Roche launched MabThera SC in the EU. In May 2016, Roche announced that the EMA approved Mabthera SC to treat patients with chronic lymphocytic leukemia (“CLL”). In June 2017, the FDA approved Genentech’s (a member of the Roche Group) RITUXAN HYCELA™, a combination of rituximab and rHuPH20 (approved and marketed under the MabThera SC brand in countries outside the U.S.), for CLL and two types of NHL, follicular lymphoma and diffuse large B-cell lymphoma. Following FDA approval, Genentech launched RITUXAN HYCELA in the U.S. Roche assumes all development, manufacturing, clinical, regulatory, sales and marketing costs under the Roche Collaboration, while we are responsible for the supply of bulk rHuPH20. We are entitled to receive reimbursements for providing research and development services and supplying bulk rHuPH20 to Roche at its request. Under the terms of the Roche Collaboration, Roche pays us a royalty on each product commercialized under the agreement consisting of a mid-single digit percent of the net sales of such product. Unless terminated earlier in accordance with its terms, the Roche Collaboration continues in effect until the expiration of Roche’s obligation to pay royalties. Roche has the obligation to pay royalties to us with respect to each product commercialized in each country, during the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the Roche Collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Payments received from Roche, excluding royalties and reimbursements for providing research and development services and supplying bulk rHuPH20, since inception of the Roche Collaboration are as follows (in thousands): As of December 31, 2017 Upfront license fee payment for the application of rHuPH20 to the initial exclusive targets $ 20,000 Election of additional exclusive targets and annual license maintenance fees for the right to designate the remaining targets as exclusive targets 23,000 Clinical development milestone payments 13,000 Regulatory milestone payments 8,000 Sales-based milestone payments 22,000 Total payments received $ 86,000 Due to our continuing involvement obligations (for example, support activities associated with rHuPH20) under the Roche Collaboration, revenues from the upfront payment, exclusive designation fees, annual license maintenance fees and sales-based milestone payments were deferred and are being amortized over the remaining term of the Roche Collaboration. For each of the years ended December 31, 2017, 2016 and 2015 , we recognized $3.3 million of Roche deferred revenues, excluding reimbursements for providing research and development services and supplying bulk rHuPH20, as revenues under collaborative agreements. Total Roche deferred revenues, excluding deferred revenues related to reimbursements for providing research and development services and supplying bulk rHuPH20, were $39.4 million and $35.7 million as of December 31, 2017 and 2016 , respectively. In September 2017, we and Roche entered into an agreement providing Roche the right to develop and commercialize products with one additional exclusive target using our ENHANZE Technology for an upfront payment of $30.0 million (the “2017 Roche Collaboration”). The upfront license payment may be followed by event-based payments subject to Roche’s achievement of specified development, regulatory and sales-based milestones. In addition, Roche will pay royalties to us if products under the collaboration are commercialized consisting of a mid-single digit percent of the net sales of such product. Unless terminated earlier in accordance with its terms, the 2017 Roche Collaboration continues in effect until the expiration of Roche’s obligation to pay royalties. Roche has the obligation to pay royalties to us with respect to each product commercialized in each country, during the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the 2017 Roche Collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Roche may terminate the agreement prior to expiration for any reason in its entirety upon 90 days prior written notice to us. Upon any such termination, the license granted to Roche (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. At the inception of the 2017 Roche Collaboration, we identified the deliverables in the arrangement to include the license, research and development services and supply of bulk rHuPH20 and determined that each individually represent separate units of accounting, because each deliverable has standalone value. The estimated selling prices for the units of accounting we identified were determined based on market conditions, the terms of comparable collaborative arrangements for similar technology in the pharmaceutical and biotech industry and entity-specific factors such as the terms of our previous collaborative agreements, our pricing practices and pricing objectives. The arrangement consideration was allocated to the deliverables based on the relative selling price method and the nature of the research and development services to be performed for the collaborator. The amount allocable to the delivered unit or units of accounting is limited to the amount that is not contingent upon the delivery of additional items or meeting other specified performance conditions (non-contingent amount). As such, we excluded from the allocable arrangement consideration the event-based payments, milestone payments and royalties regardless of the probability of receipt. Based on the results of our analysis, we allocated the $30.0 million to the license fee deliverable. We determined that the upfront payment was earned upon the granting of the worldwide, exclusive right to our technology to Roche. As a result, we recognized the $30.0 million license fee under the 2017 Roche Collaboration as revenues under collaborative agreements for the year ended December 31, 2017 . Baxalta Collaboration In September 2007, we and Baxalta entered into a collaboration and license agreement, under which Baxalta obtained a worldwide, exclusive license to develop and commercialize HYQVIA, a combination of Baxalta’s current product GAMMAGARD LIQUID ™ and our patented rHuPH20 enzyme (the “Baxalta Collaboration”). In 2013, the European Commission granted Baxalta marketing authorization in all EU Member States for the use of HYQVIA (solution for subcutaneous use), a combination of GAMMAGARD LIQUID and rHuPH20 in dual vial units, as replacement therapy for adult patients with primary and secondary immunodeficiencies, and Baxalta launched HYQVIA in the EU. In 2014, Baxalta launched HYQVIA in the U.S following the FDA’s approval of HYQVIA for treatment of adult patients with primary immunodeficiency. In May 2016, Baxalta announced that HYQVIA received a marketing authorization from the European Commission for a pediatric indication, which is being launched in Europe to treat primary and certain secondary immunodeficiencies. The Baxalta Collaboration is applicable to both kit and formulation combinations. Baxalta assumes all development, manufacturing, clinical, regulatory, sales and marketing costs under the Baxalta Collaboration, while we are responsible for the supply of bulk rHuPH20. We perform research and development activities and supply bulk rHuPH20 at the request of Baxalta, and are reimbursed by Baxalta under the terms of the Baxalta Collaboration. In addition, Baxalta has certain product development and commercialization obligations in major markets identified in the Baxalta Collaboration. Under the terms of the Baxalta Collaboration, Baxalta pays us a royalty consisting of a mid-single digit percent of the net sales of HYQVIA. Unless terminated earlier in accordance with its terms, the Baxalta Collaboration continues in effect until the expiration of Baxalta’s obligation to pay royalties to us. Baxalta has the obligation to pay royalties to us, with respect to each product commercialized in each country, during the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the Baxalta Collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Payments received from Baxalta, excluding royalties and reimbursements for providing research and development services and supplying bulk rHuPH20, since inception of the collaboration agreement are as follows (in thousands): As of December 31, 2017 Upfront license fee payment for the application of rHuPH20 to the initial exclusive target $ 10,000 Regulatory milestone payments 3,000 Sales-based milestone payments 9,000 Total payments received $ 22,000 Due to our continuing involvement obligations (for example, support activities associated with rHuPH20 enzyme), the upfront license fee and sales-based milestone payments were deferred and are being recognized over the term of the Baxalta Collaboration. For each of the years ended December 31, 2017, 2016 and 2015 , we recognized $0.8 million of Baxalta deferred revenues, excluding reimbursements for providing research and development services and supplying bulk rHuPH20, as revenues under collaborative agreements. Total Baxalta deferred revenues, excluding reimbursements for providing research and development services and supplying bulk rHuPH20, were $12.4 million and $8.2 million as of December 31, 2017 and 2016 , respectively. Other Collaborations In December 2017, we and Alexion entered into a collaboration and license agreement, under which Alexion has the worldwide license to develop and commercialize products combining our patented rHuPH20 enzyme with Alexion proprietary biologics directed at up to four targets (the “Alexion Collaboration”). Targets, once selected, will be on an exclusive, global basis. As of December 31, 2017 , Alexion has elected two specific exclusive targets. Alexion has the right to elect up to two additional targets for additional fees. The upfront license payment may be followed by event-based payments subject to Alexion’s achievement of specified development, regulatory and sales-based milestones. In addition, Alexion will pay royalties to us if products under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the Alexion Collaboration continues in effect until the later of: (i) expiration of the last to expire of the valid claims of or patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the Alexion Collaboration, with respect to each country, consists of the period equal to the longer of (a) duration of any valid claim of our patent covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Alexion may terminate the agreement prior to the expiration for any reason in its entirety upon 90 days prior written notice to us. Upon such termination, the license granted to Alexion (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. In September 2017, we and BMS entered into a collaboration and license agreement, effective November 2017, under which BMS has the worldwide license to develop and commercialize products combining our rHuPH20 enzyme with BMS proprietary biologics directed at up to eleven targets (the “BMS Collaboration”). Targets, once selected, will be on an exclusive, global basis, with the exception of one co-exclusive target. As of December 31, 2017, BMS has elected several specified exclusive targets, including programmed death 1 (PD-1), and has the right to elect additional targets, some of which are subject to additional fees. The upfront license payment may be followed by event-based payments subject to BMS’s achievement of specified development, regulatory and sales-based milestones. In addition, BMS will pay royalties to us if products developed under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the BMS Collaboration continues in effect until the later of: (i) expiration of the last to expire of the valid claims of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the BMS Collaboration, with respect to each country, consists of the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. BMS may terminate the agreement prior to expiration for any reason in its entirety upon prior written notice to us. Upon any such termination, the license granted to BMS (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. In December 2015, we and Lilly entered into a collaboration and license agreement, under which Lilly has the worldwide license to develop and commercialize products combining our patented rHuPH20 enzyme with Lilly proprietary biologics directed at up to five targets (the “Lilly Collaboration”). Targets, once selected, will be on an exclusive, global basis, with the exception of one semi-exclusive target. As of December 31, 2017 , Lilly has elected two specified exclusive targets and one specified semi-exclusive target. Lilly has the right to elect up to two additional targets for additional fees. The upfront license payment may be followed by event-based payments subject to Lilly’s achievement of specified development, regulatory and sales-based milestones. In addition, Lilly will pay royalties to us if products under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the Lilly Collaboration continues in effect until the later of: (i) expiration of the last to expire of the valid claims of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the Lilly Collaboration, with respect to each country, consists of the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Lilly may terminate the agreement prior to expiration for any reason in its entirety upon 60 days prior written notice to us. Upon any such termination, the license granted to Lilly (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. In June 2015, we and AbbVie entered into a collaboration and license agreement, under which AbbVie has the worldwide license to develop and commercialize products combining our patented rHuPH20 enzyme with AbbVie proprietary biologics directed at up to nine targets (the “AbbVie Collaboration”). Targets, once selected, will be on an exclusive, global basis. As of December 31, 2017 , AbbVie has elected one specified exclusive target, and subsequently returned the target. AbbVie has the right to elect up to eight additional targets for additional fees. The upfront license payment may be followed by event-based payments subject to AbbVie’s achievement of specified development, regulatory and sales-based milestones. In addition, AbbVie will pay tiered royalties to us if products under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the AbbVie Collaboration continues in effect until the later of: (i) expiration of the last to expire of the valid claims of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the AbbVie Collaboration, with respect to each country, consists of the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. AbbVie may terminate the agreement prior to expiration for any reason in its entirety or on a target-by-target basis upon 90 days prior written notice to us. Upon any such termination, the license granted to AbbVie (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. In December 2014, we and Janssen entered into a collaboration and license agreement, under which Janssen has the worldwide license to develop and commercialize products combining our patented rHuPH20 enzyme with Janssen proprietary biologics directed at up to five targets (the “Janssen Collaboration”). Targets, once selected, will be on an exclusive, global basis. As of December 31, 2017 , Janssen has elected one specified exclusive target. Janssen has the right to elect four additional targets in the future upon payment of additional fees. In addition, Janssen will pay royalties to us if products under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the Janssen Collaboration continues in effect until the later of (i) expiration of the last to expire of the valid claims of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the Janssen Collaboration, with respect to each country, consists of the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. In the event such valid claims expire, the royalty rate is reduced for the remaining royalty term. Janssen may terminate the agreement prior to expiration for any reason in its entirety or on a product-by-product basis upon 90 days prior written notice to us. Upon any such termination, the license granted to Janssen (in total or with respect to the terminated target, as applicable) will terminate provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. In December 2012, we and Pfizer entered into a collaboration and license agreement, under which Pfizer has the worldwide license to develop and commercialize products combining our patented rHuPH20 enzyme with Pfizer proprietary biologics directed at up to six targets (the “Pfizer Collaboration”). Targets may be selected on an exclusive or non-exclusive basis. As of December 31, 2017 , Pfizer has elected five specified exclusive targets and has returned two of its elected targets. Pfizer has the right to elect three additional targets in the future, two of which are contingent on payment of additional fees. In addition, Pfizer will pay royalties to us if products under the collaboration are commercialized. Unless terminated earlier in accordance with its terms, the Pfizer Collaboration continues in effect until the later of (i) expiration of the last to expire of the valid claims of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers a product developed under the collaboration, and (ii) expiration of the last to expire royalty term for a product developed under the collaboration. The royalty term of a product developed under the Pfizer Collaboration, with respect to each country, consists of the period equal to the longer of: (a) the duration of any valid claim of our patents covering rHuPH20 or other specified patents developed under the collaboration which valid claim covers the product in such country or (b) ten years following the date of the first commercial sale of such product in such country. Royalties are subject to adjustment as set forth in the agreement. Pfizer may terminate the agreement prior to expiration for any reason in its entirety or on a target-by-target basis upon 30 days prior written notice to us. Upon any such termination, the license granted to Pfizer (in total or with respect to the terminated target, as applicable) will terminate, provided, however, that in the event of expiration of the agreement, the licenses granted will become perpetual, non-exclusive and fully paid. Payments received under collaboration agreements for upfront license fees, license fees for the election of additional targets, maintenance fees and event-based payments since inception of the collaboration agreements are as follows (in thousands): As of December 31, 2017 Alexion Collaboration $ 40,000 BMS Collaboration 105,000 Lilly Collaboration 33,000 AbbVie Collaboration 29,000 Janssen Collaboration 30,250 Pfizer Collaboration 16,500 Total payments received $ 253,750 At the inception of the Pfizer, Janssen, AbbVie, Lilly, BMS and Alexion arrangements, we identified the deliverables in each arrangement to include the license, research and development services and supply of bulk rHuPH20. We have determined that the license, research and development services and supply of bulk rHuPH20 individually represent separate units of accounting, because each deliverable has standalone value. We determined that the rights to elect additional targets in the future upon the payment of additional license fees are substantive options that are not priced at a significant and incremental discount. Therefore, we determined for each collaboration that the rights to elect additional targets are not deliverables at the inception of the arrangement. The estimated selling prices for the units of accounting we identified were determined based on market conditions, the terms of comparable collaborative arrangements for similar technology in the pharmaceutical and biotech industry and entity-specific factors such as the terms of our previous collaborative agreements, our pricing practices and pricing objectives. The arrangement consideration was allocated to the deliverables based on the relative selling price method and the nature of the research and development services to be performed for the collaborator. The amount allocable to the delivered unit or units of accounting is limited to the amount that is not contingent upon the delivery of additional items or meeting other specified performance conditions (non-contingent amount). As such, we excluded from the allocable arrangement consideration the event-based payments, milestone payments, annual exclusivity fees and royalties regardless of the probability of receipt. Based on the results of our analysis, we allocated the following amounts to the license fee deliverable under the arrangement (in thousands): Consideration allocated to license fees: Alexion Collaboration $ 40,000 BMS Collaboration 101,400 Lilly Collaboration 33,000 AbbVie Collaboration 23,000 Janssen Collaboration 15,250 Pfizer Collaboration 12,500 Total consideration allocated to license fees $ 225,150 We determined that the consideration allocated to the license fees were earned upon the granting of the worldwide, exclusive right to our technology to the collaborators in these arrangements. As a result, we recognized the consideration allocated to license fees as revenues under collaborative agreements in the period when such license fees were earned. We recognized revenue related to event-based payments or milestone payments under these collaborations of $15.0 million , $6.0 million , and $1.0 million for the years ended December 31, 2017, 2016 and 2015 , respectively. The collaborators are each solely responsible for the development, manufacturing and marketing of any products resulting from their respective collaborations. We are entitled to receive payments for research and development services and supply of bulk rHuPH20 if requested by any collaborator. We recognize amounts allocated to research and development services as revenues under collaborative agreements as the related services are performed. We recognize amounts allocated to the sales of bulk rHuPH20 as revenues under collaborative agreements or product sales, as appropriate, when such bulk rHuPH20 has met all required specifications by the collaborators and the related title and risk of loss and damages have passed to the collaborators. We cannot predict the timing of delivery of research and development services and bulk rHuPH20 as they are at the collaborators’ requests. Pursuant to the terms of the Roche Collaboration and the Pfizer Collaboration, certain future payments meet the definition of a milestone in accordance with the Milestone Method of Accounting. We are entitled to receive additional milestone payments under our collaboration agreements with Roche and Pfizer for the successful development of the elected targets in the aggregate of up to $62.5 million upon achievement of specified clinical development milestone events and up to $12.0 million upon achievement of specified regulatory milestone events in connection with specified regulatory filings and receipt of marketing approvals.

Certain Balance Sheet Items (No

Certain Balance Sheet Items (Notes)	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Certain Balance Sheet Items	Certain Balance Sheet Items Accounts receivable, net consisted of the following (in thousands): December 31, December 31, Accounts receivable from product sales to collaborators $ 18,475 $ 7,854 Accounts receivable from revenues under collaborative agreements 2,142 6,151 Accounts receivable from other product sales 2,075 2,234 Subtotal 22,692 16,239 Allowance for distribution fees and discounts (559 ) (559 ) Total accounts receivable, net $ 22,133 $ 15,680 Inventories consisted of the following (in thousands): December 31, December 31, Raw materials $ 377 $ 761 Work-in-process 2,131 12,850 Finished goods 2,638 1,012 Total inventories $ 5,146 $ 14,623 Prepaid expenses and other assets consisted of the following (in thousands): December 31, December 31, Prepaid manufacturing expenses $ 2,337 $ 9,663 Prepaid research and development expenses 7,793 8,613 Other prepaid expenses 2,585 1,661 Other assets 6,717 1,530 Total prepaid expenses and other assets 19,432 21,467 Less long-term portion 5,553 219 Total prepaid expenses and other assets, current $ 13,879 $ 21,248 Prepaid manufacturing expenses include slot reservation fees and other amounts paid to contract manufacturing organizations. Such amounts are reclassified to work-in-process inventory once the manufacturing process has commenced. Property and equipment, net consisted of the following (in thousands): December 31, December 31, Research equipment $ 10,970 $ 10,479 Computer and office equipment 3,725 3,373 Leasehold improvements 2,715 2,331 Subtotal 17,410 16,183 Accumulated depreciation and amortization (13,890 ) (11,919 ) Property and equipment, net $ 3,520 $ 4,264 Depreciation and amortization expense was approximately $2.2 million , $2.4 million , and $1.7 million for the years ended December 31, 2017, 2016 and 2015 , respectively. Accrued expenses consisted of the following (in thousands): December 31, December 31, Accrued outsourced research and development expenses $ 18,757 $ 9,522 Accrued compensation and payroll taxes 13,384 11,539 Accrued outsourced manufacturing expenses 2,504 3,225 Other accrued expenses 5,396 4,552 Total accrued expenses 40,041 28,838 Less long-term portion 440 17 Total accrued expenses, current $ 39,601 $ 28,821 Deferred revenue consisted of the following (in thousands): December 31, December 31, Collaborative agreements License fees and event-based payments: Roche $ 39,379 $ 35,709 Other 15,999 8,209 55,378 43,918 Reimbursement for research and development services — 700 Product sales 5,487 — Total deferred revenue 60,865 44,618 Less current portion 6,568 4,793 Deferred revenue, net of current portion $ 54,297 $ 39,825

Long-Term Debt, Net (Notes)

Long-Term Debt, Net (Notes)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Long-term Debt	Long-Term Debt, Net Royalty-backed Loan In January 2016 , through our wholly-owned subsidiary Halozyme Royalty LLC (“Halozyme Royalty”), we received a $150 million loan (the “Royalty-backed Loan”) pursuant to a credit agreement (the “Credit Agreement”) with BioPharma Credit Investments IV Sub, LP and Athyrium Opportunities II Acquisition LP (the “Royalty-backed Lenders”). Under the terms of the Credit Agreement, Halozyme Therapeutics, Inc. transferred to Halozyme Royalty the right to receive royalty payments from the commercial sales of ENHANZE products owed under the Roche Collaboration and Baxalta Collaboration (“Collaboration Agreements”). The royalty payments from the Collaboration Agreements will be used to repay the principal and interest on the loan (the “Royalty Payments”). The Royalty-backed Loan bears interest at a per annum rate of 8.75% plus the three-month LIBOR rate . The three-month LIBOR rate is subject to a floor of 0.7% and a cap of 1.5% . The interest rate as of December 31, 2017 and 2016 was 10.25% and 9.71% , respectively. The Credit Agreement provides that none of the Royalty Payments were required to be applied to the Royalty-backed Loan prior to January 1, 2017, 50% of the Royalty Payments are required to be applied to the Royalty-backed Loan between January 1, 2017 and January 1, 2018 and thereafter all Royalty Payments must be applied to the Royalty-backed Loan. However, the amounts available to repay the Royalty-backed Loan are subject to caps of $13.75 million per quarter in 2017, $18.75 million per quarter in 2018, $21.25 million per quarter in 2019 and $22.5 million per quarter in 2020 and thereafter. Amounts available to repay the Royalty-backed Loan will be applied first to pay interest and second to repay principal on the Royalty-backed Loan. Any accrued interest that is not paid on any applicable quarterly payment date, as defined, will be capitalized and added to the principal balance of the Royalty-backed Loan on such date. Halozyme Royalty will be entitled to receive and distribute to Halozyme any Royalty Payments that are not required to be applied to the Royalty-backed Loan or which are in excess of the foregoing caps. Because the repayment of the term loan is contingent upon the level of Royalty Payments received, the repayment term may be shortened or extended depending on the actual level of Royalty Payments. The final maturity date of the Royalty-backed Loan will be the earlier of (i) the date when principal and interest is paid in full, (ii) the termination of Halozyme Royalty’s right to receive royalties under the Collaboration Agreements, and (iii) December 31, 2050 . Currently, we estimate that the loan will be repaid in the first quarter of 2020. This estimate could be adversely affected and the repayment period could be extended if future royalty amounts are less than currently expected. Under the terms of the Credit Agreement, at any time after January 1, 2019, Halozyme Royalty may, subject to certain limitations, prepay the outstanding principal of the Royalty-backed Loan in whole or in part, at a price equal to 105% of the outstanding principal on the Royalty-backed Loan, plus accrued but unpaid interest. The Royalty-backed Loan constitutes an obligation of Halozyme Royalty, and is non-recourse to Halozyme. Halozyme Royalty retains its right to the Royalty Payments following repayment of the loan. As of December 31, 2017 , we were in compliance with all covenants under the Royalty-backed Loan and there was no material adverse change in our business, operations or financial condition. During the year ended December 31, 2016 , accrued interest in the amount of $13.2 million was capitalized and added to the principal balance of the Royalty-backed Loan. We began making principal and interest payments against the Royalty-backed Loan in the first quarter of 2017 and therefore had no capitalized interest in the year ended December 31, 2017 . In addition, we recorded accrued interest, which is included in accrued expenses, of $0.7 million as of December 31, 2017 and 2016 , respectively. In connection with the Royalty-backed Loan, we paid the Royalty-backed Lenders a fee of $1.5 million and incurred additional debt issuance costs totaling $0.4 million , which includes expenses that we paid on behalf of the Royalty-backed Lenders and expenses incurred directly by us. Debt issuance costs and the lender fee have been netted against the debt as of December 31, 2017 , and are being amortized over the estimated term of the debt using the effective interest method. For the years ended December 31, 2017 and 2016, the Company recognized interest expense, including amortization of the debt discount, related to the Royalty-backed Loan of $16.4 million and $14.5 million , respectively. The assumptions used in determining the expected repayment term of the debt and amortization period of the issuance costs requires that we make estimates that could impact the short- and long-term classification of these costs, as well as the period over which these costs will be amortized. The outstanding balance of the Royalty-backed Loan as of December 31, 2017 was $146.5 million , net of unamortized debt discount of $0.8 million . Oxford and SVB Loan and Security Agreement In December 2013, we entered into an Amended and Restated Loan and Security Agreement (the “Original Loan Agreement”) with Oxford Finance LLC (“Oxford”) and Silicon Valley Bank (“SVB”) (collectively, the “Lenders”), amending and restating in its entirety our previous loan agreement with the Lenders, dated December 2012. The Original Loan Agreement provided for an additional $20 million principal amount of new term loan, bringing the total term loan balance to $50 million . The amended term loan facility was scheduled to mature on January 1, 2018 . In January 2015, we entered into the second amendment to the Original Loan Agreement with the Lenders, amending and restating the term loan repayment schedules of the Original Loan Agreement. The amended and restated term loan repayment schedule provided for interest only payments through January 2016, followed by consecutive equal monthly payments of principal and interest in arrears starting in February 2016 and continuing through the previously established maturity date of January 1, 2018. Consistent with the original loan, the amended Original Loan Agreement provided for a 7.55% interest rate on the term loan and a final payment equal to 8.5% of the original principal amount, or $4.25 million , which was due when the term loan became due or upon the prepayment of the facility. In June 2016 , we entered into a Loan and Security Agreement (the “Loan Agreement”) with the Lenders, providing a senior secured loan facility of up to an aggregate principal amount of $70.0 million , comprising a $55.0 million draw in June 2016 and an additional $15.0 million tranche, which we had the option to draw during the second quarter of 2017 and did not exercise. The initial proceeds carry an interest rate of 8.25% and were partially used to pay the outstanding principal and final payment of $4.25 million owed on the Original Loan Agreement with the Lenders. The remaining proceeds are being used for working capital and general business requirements. The repayment schedule provides for interest only payments for the first 18 months , followed by consecutive equal monthly payments of principal and interest in arrears through the maturity date of January 1, 2021 . The Loan Agreement provides for a final payment equal to 5.50% of the initial $55.0 million principal amount. The final payment is due when the Loan Agreement becomes due or upon the prepayment of the facility. We have the option to prepay the outstanding balance of the Loan Agreement in full, subject to a prepayment fee of 2% in the first year and 1% in the second year of the Loan Agreement. In connection with the Loan Agreement, the debt offering costs have been recorded as a debt discount in our condensed consolidated balance sheets which, together with the final payment and fixed interest rate payments, are being amortized and recorded as interest expense throughout the life of the loan using the effective interest rate method. The Loan Agreement is secured by substantially all of the assets of the Company and our subsidiary, Halozyme, Inc., except that the collateral does not include any equity interests in Halozyme, Inc., any of our intellectual property (including all licensing, collaboration and similar agreements relating thereto), and certain other excluded assets. The Loan Agreement contains customary representations, warranties and covenants by us, which covenants limit our ability to convey, sell, lease, transfer, assign or otherwise dispose of certain of our assets; engage in any business other than the businesses currently engaged in by us or reasonably related thereto; liquidate or dissolve; make certain management changes; undergo certain change of control events; create, incur, assume, or be liable with respect to certain indebtedness; grant certain liens; pay dividends and make certain other restricted payments; make certain investments; make payments on any subordinated debt; enter into transactions with any of our affiliates outside of the ordinary course of business or permit our subsidiaries to do the same; and make any voluntary prepayment of or modify certain terms of the Royalty-backed Loan. In addition, subject to certain exceptions, we are required to maintain with SVB our primary deposit accounts, securities accounts and commodities, and to do the same for our subsidiary, Halozyme, Inc. The Loan Agreement also contains customary indemnification obligations and customary events of default, including, among other things, our failure to fulfill certain of our obligations under the Loan Agreement and the occurrence of a material adverse change which is defined as a material adverse change in our business, operations, or condition (financial or otherwise), a material impairment of the prospect of repayment of any portion of the loan, a material impairment in the perfection or priority of the Lender’s lien in the collateral or in the value of such collateral or the occurrence of an event of default under the Royalty-backed Loan. In the event of default by us under the Loan Agreement, the Lenders would be entitled to exercise their remedies thereunder, including the right to accelerate the debt, upon which we may be required to repay all amounts then outstanding under the Loan Agreement, which could harm our financial condition. As of December 31, 2017 , we were in compliance with all covenants under the Loan Agreement and there was no material adverse change in our business, operations or financial condition. Interest expense, including amortization of the debt discount, related to the Loan Agreement totaled $5.5 million , $20.0 million and $5.2 million for the years ended December 31, 2017, 2016 and 2015 , respectively. Accrued interest, which is included in accrued expenses, was $0.4 million and $1.1 million as of December 31, 2017 and 2016 , respectively. The outstanding term loan balance was $55.9 million as of December 31, 2017 , inclusive of $1.3 million of accretion of the final payment and net of unamortized debt discount related to offering costs of $0.4 million . Future maturities and interest payments of long-term debt as of December 31, 2017 , are as follows (in thousands): 2018 $ 94,125 2019 105,758 2020 27,311 2021 4,755 2022 — Total minimum payments 231,949 Less amount representing interest (26,792 ) Gross balance of long-term debt 205,157 Less unamortized debt discount (2,806 ) Present value of long-term debt 202,351 Less current portion of long-term debt (77,211 ) Long-term debt, less current portion and unamortized debt discount $ 125,140

Share-based Compensation (Notes

Share-based Compensation (Notes)	12 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	Share-based Compensation We currently grant stock options, restricted stock awards and restricted stock units under the Amended and Restated 2011 Stock Plan (“2011 Stock Plan”), which wa s approved by the stockholders on May 6, 2016 an d provides for the grant of up to 44.2 million shares of common stock to selected employees, consultants and non-employee members of our Board of Directors as stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and performance awards. The 2011 Stock Plan was approved by the stockholders. Awards are subject to terms and conditions established by the Compensation Committee of our Board of Directors. During the year ended December 31, 2017 , we granted share-based awards under the 2011 Stock Plan. At December 31, 2017 , 13,023,641 shares were subject to outstanding awards and 6,552,249 shares were available for future grants of share-based awards. Total share-based compensation expense related to share-based awards was comprised of the following (in thousands): Year Ended December 31, 2017 2016 2015 Research and development $ 13,080 $ 11,470 $ 9,795 Selling, general and administrative 17,590 14,115 11,043 Share-based compensation expense $ 30,670 $ 25,585 $ 20,838 Share-based compensation expense by type of share-based award (in thousands): Year Ended December 31, 2017 2016 2015 Stock options $ 19,583 $ 16,544 $ 11,145 RSAs, RSUs and PRSUs 11,087 9,041 9,693 $ 30,670 $ 25,585 $ 20,838 Total unrecognized estimated compensation cost by type of award and the weighted-average remaining requisite service period over which such expense is expected to be recognized (in thousands, unless otherwise noted): December 31, 2017 Unrecognized Expense Remaining Weighted-Average Recognition Period (years) Stock options $ 36,914 2.4 RSAs $ 4,610 1.6 RSUs $ 15,965 2.6 Cash flows resulting from tax deductions in excess of the cumulative compensation cost recognized for options exercised (excess tax benefits) are classified as cash inflows provided by financing activities and cash outflows used in operating activities. Stock Options. Options granted under the Plans must have an exercise price equal to at least 100% of the fair market value of our common stock on the date of grant. The options generally have a maximum contractual term of ten years and vest at the rate of one-fourth of the shares on the first anniversary of the date of grant and 1/48 of the shares monthly thereafter. Certain option awards provide for accelerated vesting if there is a change in control (as defined in the Plans). A summary of our stock option award activity as of and for the years ended December 31, 2017, 2016 and 2015 is as follows: Shares Weighted Weighted Aggregate Outstanding at January 1, 2015 6,353,892 $9.18 Granted 3,973,604 $16.26 Exercised (1,926,368 ) $7.49 Canceled/forfeited (407,936 ) $10.64 Outstanding at December 31, 2015 7,993,192 $13.03 Granted 4,466,306 $9.03 Exercised (413,248 ) $6.88 Canceled/forfeited (955,054 ) $12.42 Outstanding at December 31, 2016 11,091,196 $11.70 Granted 2,717,614 $12.60 Exercised (1,514,826 ) $9.24 Canceled/forfeited (1,185,518 ) $11.89 Outstanding at December 31, 2017 11,108,466 $12.24 7.0 $90.8 million Vested and expected to vest at December 31, 2017 11,108,466 $12.24 7.0 $90.8 million Exercisable at December 31, 2017 5,493,802 $12.31 6.1 $44.7 million The weighted average grant date fair values of options granted during the years ended December 31, 2017, 2016 and 2015 were $7.86 per share, $5.36 per share and $9.60 per share, respectively. The total intrinsic value of options exercised during the years ended December 31, 2017, 2016 and 2015 was approximately $10.0 million , $1.4 million and $16.2 million , respectively. Cash received from stock option exercises for the years ended December 31, 2017, 2016 and 2015 was approximately $14.0 million , $2.8 million and $14.4 million , respectively. The exercise price of stock options granted is equal to the closing price of the common stock on the date of grant. The fair value of each option award is estimated on the date of grant using the Black-Scholes-Merton option pricing model (“Black-Scholes model”). Expected volatility is based on historical volatility of our common stock. The expected term of options granted is based on analyses of historical employee termination rates and option exercises. The risk-free interest rate is based on the U.S. Treasury yield for a period consistent with the expected term of the option in effect at the time of the grant. The dividend yield assumption is based on the expectation of no future dividend payments. The assumptions used in the Black-Scholes model were as follows: Year Ended December 31, 2017 2016 2015 Expected volatility 69.8-71.7% 67.5-71.9% 66.2-67.4% Average expected term (in years) 5.6 5.4 5.6 Risk-free interest rate 1.73-2.13% 1.00-1.90% 1.34-1.92% Expected dividend yield — — — Restricted Stock Awards . RSAs are grants that entitle the holder to acquire shares of our common stock at zero cost. The shares covered by a RSA cannot be sold, pledged, or otherwise disposed of until the award vests and any unvested shares may be reacquired by us for the original purchase price following the awardee’s termination of service. The RSAs will generally vest at the rate of one-fourth of the shares on each anniversary of the date of grant. Annual grants of RSAs to the Board of Directors typically vest in approximately one year. The following table summarizes our RSA activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Unvested at January 1, 2015 1,158,451 $10.26 Granted 515,695 $15.00 Vested (721,990 ) $10.11 Forfeited (140,676 ) $11.84 Unvested at December 31, 2015 811,480 $13.13 Granted 968,652 $8.41 Vested (296,831 ) $12.76 Forfeited (180,198 ) $10.33 Unvested at December 31, 2016 1,303,103 $10.09 Granted 98,945 $14.15 Vested (514,613 ) $10.23 Forfeited (108,485 ) $9.62 Unvested at December 31, 2017 778,950 $10.59 The estimated fair value of the RSAs was based on the closing market value of our common stock on the date of grant. The total grant date fair value of RSAs vested during the years ended December 31, 2017, 2016 and 2015 was approximately $5.3 million , $3.8 million and $7.3 million , respectively. The fair value of RSAs vested during the years ended December 31, 2017, 2016 and 2015 , was approximately $6.6 million , $2.5 million and $13.9 million , respectively. Restricted Stock Units . A RSU is a promise by us to issue a share of our common stock upon vesting of the unit. The RSUs will generally vest at the rate of one-fourth of the shares on each anniversary of the date of grant. The following table summarizes our RSU activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Weighted Aggregate Unvested at January 1, 2015 462,322 $11.12 Granted 422,492 $14.75 Vested (134,088 ) $10.93 Forfeited (84,512 ) $10.86 Outstanding at December 31, 2015 666,214 $13.49 Granted 796,582 $8.17 Vested (218,279 ) $12.74 Forfeited (77,948 ) $10.99 Outstanding at December 31, 2016 1,166,569 $10.16 Granted 1,378,273 $12.13 Vested (378,406 ) $10.48 Forfeited (251,261 ) $11.11 Outstanding at December 31, 2017 1,915,175 $11.39 1.4 $38.8 million The estimated fair value of the RSUs was based on the closing market value of our common stock on the date of grant. The total grant date fair value of RSUs vested during the years ended December 31, 2017, 2016 and 2015 was approximately $4.0 million , $2.8 million and $1.5 million , respectively. The fair value of RSUs vested during the years ended December 31, 2017, 2016 and 2015 was approximately $4.7 million , $2.1 million and $1.8 million , respectively. Performance Restricted Stock Units . A PRSU is a promise by us to issue a share of our common stock upon achievement of a specific performance condition. The following table summarizes our PRSU activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Average Grant Date Fair Value Outstanding at January 1, 2015 431,238 $8.91 Granted 118,209 $11.19 Vested (83,380 ) $9.48 Forfeited (156,360 ) $9.21 Outstanding at December 31, 2015 309,707 $9.48 Granted — — Vested (30,037 ) $9.49 Forfeited (79,415 ) $9.44 Outstanding at December 31, 2016 200,255 $9.49 Granted — — Vested — — Forfeited (200,255 ) $9.49 Outstanding at December 31, 2017 — — The estimated fair value of the PRSUs was based on the closing market value of our common stock on the date of grant. The total grant date fair value and intrinsic value of PRSUs vested during the years ended December 31, 2017, 2016 and 2015 was approximately zero , $0.3 million and $0.8 million , respectively.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity (Deficit)	Stockholders’ Equity (Deficit) In May 2017, we completed an underwritten public offering pursuant to which we sold 11.5 million shares of common stock, including 1.5 million shares sold pursuant to the full exercise of an option to purchase additional shares granted to the underwriters. All of the shares were offered at a public offering price of $12.50 per share, generating $134.9 million in net proceeds, after deducting underwriting discounts and commissions and other offering expenses. We intend to use the net proceeds from this offering to fund continued development of our PEGPH20 oncology program and for other general corporate purposes. During the years ended December 31, 2017, 2016 and 2015 , we issued an aggregate of 1,514,826 , 413,248 and 1,926,368 shares of common stock, respectively, in connection with the exercises of stock options, for net proceeds of approximately $14.0 million , $2.8 million and $14.4 million , respectively. For the years ended December 31, 2017, 2016 and 2015 , we issued 281,398 , 134,944 and 82,069 shares of common stock, respectively, upon vesting of certain RSUs for which the RSU holders surrendered 97,008 , 83,335 and 52,019 RSUs, respectively, to pay for minimum withholding taxes totaling approximately $1.9 million , $0.8 million and $0.7 million , respectively. In addition, we canceled 9,540 shares of common stock, net of issuances and issued 780,066 and 375,019 shares of common stock, net of cancellations in connection with grants of RSAs during the years ended December 31, 2017, 2016 and 2015 , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases Our administrative offices and research facilities are located in San Diego, California. We lease an aggregate of approximately 76,000 square feet of office and research space in four buildings. The leases commenced in June 2011 and November 2013 and continue through January 2023 . The leases are subject to approximately 3.0% annual increases throughout the terms of the leases. We also pay a pro rata share of operating costs, insurance costs, utilities and real property taxes. We received incentives under the leases, including tenant improvement allowances and reduced or free rent, for which the unamortized deferred rent balances associated with these incentives was $0.3 million and $0.4 million as of December 31, 2017 and 2016, respectively. In November 2015, we opened a satellite office in South San Francisco, California. We lease approximately 10,000 square feet of office space. The lease commenced in November 2015 and continues through January 2021 . The lease is subject to approximately 3.0% annual increases throughout the term of the lease. We also pay a pro rata share of operating costs, insurance costs, utilities and real property taxes. We received incentives under the lease, including tenant improvement allowances and reduced or free rent, for which the unamortized deferred rent balances associated with these incentives was $0.3 million and $0.4 million as of December 31, 2017 and 2016, respectively. Additionally, we lease certain office equipment under operating leases. Total rent expense was approximately $2.3 million , $2.2 million and $1.9 million for the years ended December 31, 2017, 2016 and 2015 , respectively. Approximate annual future minimum operating lease payments as of December 31, 2017 are as follows (in thousands): Year: Operating 2018 $ 2,415 2019 2,785 2020 2,824 2021 2,470 2022 2,506 Total minimum lease payments $ 13,000 Other Commitments In March 2010, we entered into a second Commercial Supply Agreement with Avid (the “Avid Commercial Supply Agreement”). Under the terms of the Avid Commercial Supply Agreement, we are committed to certain minimum annual purchases of bulk rHuPH20 equal to three quarters of forecasted supply. In addition, Avid has the right to manufacture and supply a certain percentage of bulk rHuPH20 that will be used in the collaboration products. At December 31, 2017 , we had a $7.2 million minimum purchase obligation in connection with this agreement. In June 2011, we entered into a services agreement with Patheon for the technology transfer and manufacture of Hylenex recombinant. At December 31, 2017 , we had a $0.3 million minimum purchase obligation in connection with this agreement. Contingencies We have entered into an in-licensing agreement with a research organization, which is cancelable at our option with 90 days written notice. Under the terms of this agreement, we have received a license to the know-how and technology claimed, in certain patents or patent applications. We are required to pay fees, milestones and/or royalties on future sales of products employing the technology or falling under claims of a patent, and some of the agreements require minimum royalty payments. We continually reassess the value of the license agreement. If the in-licensed and research candidate is successfully developed, we may be required to pay milestone payments of approximately $8.0 million over the life of this agreement in addition to royalties on sales of the affected products. Due to the uncertainties of the development process, the timing and probability of the remaining milestone and royalty payments cannot be accurately estimated. Legal Contingencies From time to time, we may be involved in disputes, including litigation, relating to claims arising out of operations in the normal course of our business. Any of these claims could subject us to costly legal expenses and, while we generally believe that we have adequate insurance to cover many different types of liabilities, our insurance carriers may deny coverage or our policy limits may be inadequate to fully satisfy any damage awards or settlements. If this were to happen, the payment of any such awards could have a material adverse effect on our consolidated results of operations and financial position. Additionally, any such claims, whether or not successful, could damage our reputation and business. We currently are not a party to any legal proceedings, the adverse outcome of which, in management’s opinion, individually or in the aggregate, would have a material adverse effect on our consolidated results of operations or financial position.

Income Taxes (Notes)

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Total income (loss) before income taxes summarized by region were as follows (in thousands): Year Ended December 31, 2017 2016 2015 United States $ 160,938 $ 6,384 $ 11,724 Foreign (99,328 ) (108,245 ) (43,955 ) Net income (loss) before income taxes $ 61,610 $ (101,861 ) $ (32,231 ) Significant components of our net deferred tax assets/(liabilities) were as follows (in thousands). December 31, 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 32,630 $ 103,296 Deferred revenue 8,815 15,354 Research and development and orphan drug credits 75,224 73,701 Share-based compensation 7,423 8,844 Alternative minimum tax credit 5,532 1,494 Other, net 2,270 1,021 131,894 203,710 Valuation allowance for deferred tax assets (126,189 ) (203,370 ) Deferred tax assets, net of valuation 5,705 340 Deferred tax liabilities: Depreciation (173 ) (340 ) Total deferred tax liabilities (173 ) (340 ) Net deferred tax asset (liability) $ 5,532 $ — A valuation allowance of $126.2 million and $203.4 million has been established to offset the net deferred tax assets as of December 31, 2017 and 2016 , respectively, as realization of such assets is uncertain. Under the Act, the AMT credit carryovers can be used to offset regular tax liability for taxable years beginning after 2017. If not utilized before 2022, any remaining AMT credit carryover will be fully refundable. Accordingly, the recognized deferred tax asset, on a provisional basis, as of December 31, 2017 is the AMT credit carryover that will either be utilized or refunded. Income tax expense was comprised of the following components (in thousands): Year Ended December 31, 2017 2016 2015 Current - federal $ 4,051 $ 1,145 $ — Current - state 120 17 — Deferred - federal (5,532 ) — — Deferred - state — — — $ (1,361 ) $ 1,162 $ — The provision for income taxes on earnings subject to income taxes differs from the statutory federal income tax rate due to the following (in thousands): Year Ended December 31, 2017 2016 2015 Federal income tax expense (benefit) at 34% $ 20,947 $ (34,633 ) $ (10,959 ) State income tax benefit, net of federal income tax impact 930 (653 ) 5,524 (Decrease) increase in valuation allowance (77,181 ) 11,252 4,045 Enactment of the Tax Cuts and Jobs Act 17,132 — — Foreign income subject to tax at other than federal statutory rate 33,674 36,803 14,945 Shared-based compensation 525 3,735 (4,990 ) Non-deductible expenses and other 5,779 698 6,457 Research and development credits, net 4,162 (1,084 ) (3,861 ) Orphan drug credits, net of federal add back (7,329 ) (14,956 ) (11,161 ) $ (1,361 ) $ 1,162 $ — At December 31, 2017 , our unrecognized tax benefit and uncertain tax positions were $14.4 million . None of this amount would affect the effective tax rate and $14.4 million would affect the effective tax rate in the event the valuation allowance was removed. Of the unrecognized tax benefits, we do not expect any significant changes to occur in the next 12 months. Interest and/or penalties related to uncertain income tax positions are recognized by us as a component of income tax expense. For the years ended December 31, 2017, 2016 and 2015 , we recognized no interest or penalties. The following table summarizes the activity related to our unrecognized tax benefits (in thousands): Year Ended December 31, 2017 2016 2015 Gross unrecognized tax benefits at beginning of period $ 12,799 $ 4,898 $ — Increases in tax positions for prior years — 5,615 — Decreases in tax positions for prior years (2,518 ) (4,898 ) — Increases in tax positions for current year 4,147 7,184 4,898 Gross unrecognized tax benefits at end of period $ 14,428 $ 12,799 $ 4,898 At December 31, 2017 , we had federal, California and other state tax net operating loss carryforwards of approximately $88.5 million , $243.1 million and $13.9 million , respectively. The following table shows key expiration dates of the federal and California net operating loss carryforwards (in thousands): Expires in: Net Operating Loss 2018 2021 and beyond 2028 and beyond Federal $ 88,516 — $ 88,516 — California $ 243,080 — — $ 243,080 At December 31, 2017 , we had federal and California research and development tax credit carryforwards of approximately $19.1 million and $11.7 million , respectively. The federal research and development tax credits will begin to expire in 2024 unless previously utilized. The California research and development tax credits will carryforward indefinitely until utilized. Additionally, we had Orphan Drug Credit carryforwards of $57.3 million which will begin to expire in 2035 . Pursuant to Internal Revenue Code Section 382, the annual use of the net operating loss carryforwards and research and development tax credits could be limited by any greater than 50% ownership change during any three year testing period. As a result of any such ownership change, portions of our net operating loss carryforwards and research and development tax credits are subject to annual limitations. A Section 382 analysis regarding the limitation of the net operating losses and research and development credits was completed as of November 1, 2017. Based upon the analysis, we do not believe an ownership change occurred during 2017. Based upon previous analysis it was determined that ownership changes occurred in prior years; however, the annual limitations on net operating loss and research and development tax credit carryforwards will not have a material impact on the future utilization of such carryforwards. We do not provide for U.S. income taxes on the undistributed earnings of our foreign subsidiaries as it is our intention to utilize those earnings in the foreign operations for an indefinite period of time. At December 31, 2017 and 2016 , there were no undistributed earnings in foreign subsidiaries. We are subject to taxation in the U.S. and in various state and foreign jurisdictions. Our tax years for 1998 and forward are subject to examination by the U.S. and California tax authorities due to the carryforward of unutilized net operating losses and research and development credits. A new Swiss subsidiary, Halozyme Switzerland GmbH, was formed during the fourth quarter of 2016 and obtained a tax ruling from Canton of Basel Stadt for its operations in Switzerland. The tax ruling is dated December 21, 2016, and will continue for a period of ten years, not to extend beyond December 31, 2026. The combined income tax burden at the federal, cantonal and communal level will not exceed 10% during the period covered by the ruling. As a result of foreign losses and a full valuation allowance, no net tax benefit was derived for the year ended December 31, 2017 as a result of the tax ruling.

Employee Savings Plan (Notes)

Employee Savings Plan (Notes)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Compensation and Employee Benefit Plans [Text Block]	Employee Savings Plan We have an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code. All employees are eligible to participate, provided they meet the requirements of the plan. We are not required to make matching contributions under the plan. However, we voluntarily contributed to the plan approximately $1.2 million , $1.0 million and $0.7 million for the years ended December 31, 2017, 2016 and 2015 , respectively.

Summary of Unaudited Quarterly

Summary of Unaudited Quarterly Financial Information (Notes)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Summary of Unaudited Quarterly Financial Information The following is a summary of our unaudited quarterly results for the years ended December 31, 2017 and 2016 (in thousands): Quarter Ended 2017 (Unaudited): March 31, June 30, September 30, December 31, Total revenues (1) (2) $ 29,568 $ 33,750 $ 63,731 $ 189,564 Gross profit on product sales $ 3,890 $ 4,992 $ 5,257 $ 5,105 Total operating expenses $ 57,094 $ 59,228 $ 55,654 $ 63,635 Net income (loss) $ (32,897 ) $ (30,763 ) $ 2,749 $ 123,882 Net income (loss) per share: Basic $ (0.26 ) $ (0.23 ) $ 0.02 $ 0.87 Diluted $ (0.26 ) $ (0.23 ) $ 0.02 $ 0.85 Shares used in computing net income (loss) per share: Basic 128,615 134,013 141,190 141,718 Diluted 128,615 134,013 143,236 145,633 Quarter Ended 2016 (Unaudited): March 31, June 30, September 30, December 31, Total revenues $ 42,499 $ 33,336 $ 31,853 $ 39,003 Gross profit on product sales $ 5,178 $ 5,391 $ 4,197 $ 5,420 Total operating expenses $ 58,668 $ 55,059 $ 54,596 $ 61,578 Net loss $ (19,816 ) $ (26,875 ) $ (28,946 ) $ (27,386 ) Net loss per share, basic and diluted $ (0.16 ) $ (0.21 ) $ (0.23 ) $ (0.21 ) Shares used in computing basic and diluted net loss per share 127,615 127,958 128,154 128,185 _______________ (1) Revenues for the quarter ended December 31, 2017 included $101.4 million , $40.0 million and $15.0 million in revenue under collaborative arrangements from BMS, Alexion and Janssen, respectively. (2) Revenues for the quarter ended September 30, 2017 included $30.0 million in revenue under collaborative arrangements from the 2017 Roche Collaboration.

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts (Notes)	12 Months Ended
	Dec. 31, 2017
Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	Valuation and Qualifying Accounts (in thousands) Balance at Beginning of Period Additions Deductions Balance at End of Period For the year ended December 31, 2017 Accounts receivable allowances (1) $ 559 $ 4,645 $ (4,645 ) $ 559 For the year ended December 31, 2016 Accounts receivable allowances (1) $ 967 $ 4,795 $ (5,203 ) $ 559 For the year ended December 31, 2015 Accounts receivable allowances (1) $ 611 $ 4,150 $ (3,794 ) $ 967 _______________ (1) Allowances are for chargebacks, prompt payment discounts and distribution fees related to Hylenex recombinant product sales.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Halozyme Therapeutics, Inc. and our wholly owned subsidiary, Halozyme, Inc., and Halozyme, Inc.’s wholly owned subsidiaries, Halozyme Holdings Ltd., Halozyme Royalty LLC, Halozyme Switzerland GmbH and Halozyme Switzerland Holdings GmbH. All intercompany accounts and transactions have been eliminated.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in our consolidated financial statements and accompanying notes. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates.
Cash Equivalents	Cash Equivalents and Marketable Securities Cash equivalents consist of highly liquid investments, readily convertible to cash, that mature within ninety days or less from the date of purchase. As of December 31, 2017 , our cash equivalents consisted of money market funds and commercial paper.
Marketable Securities	Marketable securities are investments with original maturities of more than ninety days from the date of purchase that are specifically identified to fund current operations. Marketable securities are considered available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date which reflects management’s intention to use the proceeds from the sale of these investments to fund our operations, as necessary. Such available-for-sale investments are carried at fair value with unrealized gains and losses recorded in other comprehensive gain (loss) and included as a separate component of stockholders’ equity (deficit). The cost of marketable securities is adjusted for amortization of premiums or accretion of discounts to maturity, and such amortization or accretion is included in investment and other income, net in the condensed consolidated statements of operations. We use the specific identification method for calculating realized gains and losses on marketable securities sold. Realized gains and losses and declines in value judged to be other-than-temporary on marketable securities, if any, are included in investment and other income, net in the consolidated statements of operations.
Restricted Cash	Restricted Cash Under the terms of the leases of our facilities, we are required to maintain letters of credit as security deposits during the terms of such leases.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The authoritative guidance for fair value measurements establishes a three tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, available-for-sale marketable securities, accounts receivable, prepaid expenses and other assets, accounts payable, accrued expenses and long-term debt. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The carrying amount of cash equivalents, accounts receivable, prepaid expenses and other assets, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on Level 3 inputs and the borrowing rates currently available for loans with similar terms, we believe the fair value of long-term debt approximates its carrying value. Available-for-sale marketable securities consist of corporate debt securities, U.S. Treasury securities and commercial paper, and are measured at fair value using Level 1 and Level 2 inputs. Level 2 financial instruments are valued using market prices on less active markets and proprietary pricing valuation models with observable inputs, including interest rates, yield curves, maturity dates, issue dates, settlement dates, reported trades, broker-dealer quotes, issue spreads, benchmark securities or other market related data. We obtain the fair value of Level 2 investments from our investment manager, who obtains these fair values from a third-party pricing source. We validate the fair values of Level 2 financial instruments provided by our investment manager by comparing these fair values to a third-party pricing source.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentrations of Credit Risk, Sources of Supply and Significant Customers We are subject to credit risk from our portfolio of cash equivalents and marketable securities. These investments were made in accordance with our investment policy which specifies the categories, allocations, and ratings of securities we may consider for investment. The primary objective of our investment activities is to preserve principal while at the same time maximizing the income we receive without significantly increasing risk. We maintain our cash and cash equivalent balances with one major commercial bank and marketable securities with another financial institution. Deposits held with the financial institutions exceed the amount of insurance provided on such deposits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash, cash equivalents and marketable securities to the extent recorded on the consolidated balance sheets. We are also subject to credit risk from our accounts receivable related to our product sales and revenues under our license and collaborative agreements. We have license and collaborative agreements with pharmaceutical companies under which we receive payments for license fees, milestone payments for specific achievements designated in the collaborative agreements, reimbursements of research and development services and supply of bulk formulation of rHuPH20. In addition, we sell Hylenex ® recombinant in the United States to a limited number of established wholesale distributors in the pharmaceutical industry. Credit is extended based on an evaluation of the customer’s financial condition, and collateral is not required. Management monitors our exposure to accounts receivable by periodically evaluating the collectibility of the accounts receivable based on a variety of factors including the length of time the receivables are past due, the financial health of the customer and historical experience.
Trade and Other Accounts Receivable, Policy [Policy Text Block]	Accounts Receivable, Net Accounts receivable is recorded at the invoiced amount and is non-interest bearing. Accounts receivable is recorded net of allowances for doubtful accounts, cash discounts for prompt payment, distribution fees and chargebacks.
Inventory, Policy [Policy Text Block]	Inventories Inventories are stated at lower of cost or net realizable value. Cost is determined on a first-in, first-out basis. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. Inventories are reviewed periodically for potential excess, dated or obsolete status. We evaluate the carrying value of inventories on a regular basis, taking into account such factors as historical and anticipated future sales compared to quantities on hand, the price we expect to obtain for products in their respective markets compared with historical cost and the remaining shelf life of goods on hand. Prior to receiving marketing approval from the U.S. Food and Drug Administration (“FDA”) or comparable regulatory agencies in foreign countries, costs related to purchases of bulk rHuPH20 and raw materials and the manufacturing of the product candidates are recorded as research and development expense. All direct manufacturing costs incurred after receiving marketing approval are capitalized as inventory. Inventories used in clinical trials are expensed at the time the inventories are packaged for the clinical trials.
Property and Equipment, Policy [Policy Text Block]	Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization. Equipment is depreciated using the straight-line method over its estimated useful life of three years and leasehold improvements are amortized using the straight-line method over the estimated useful life of the asset or the lease term, whichever is shorter.
Impairment of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-Lived Assets We account for long-lived assets in accordance with authoritative guidance for impairment or disposal of long-lived assets. Long-lived assets are reviewed for events or changes in circumstances, which indicate that their carrying value may not be recoverable.
Deferred Charges, Policy [Policy Text Block]	Deferred Rent Rent expense is recorded on a straight-line basis over the initial term of the lease. The difference between rent expense accrued and amounts paid under lease agreements is recorded as deferred rent and is included in accrued expenses and other long-term liabilities, as applicable, in the accompanying consolidated balance sheets.
Comprehensive Income (Loss), Policy [Policy Text Block]	Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity during the period from transactions and other events and circumstances from non-owner sources.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition We generate revenues from product sales and payments received under collaborative agreements. Collaborative agreement payments may include nonrefundable fees at the inception of the agreements, license fees, milestone and event-based payments for specific achievements designated in the collaborative agreements, reimbursements of research and development services and supply of bulk rHuPH20, and/or royalties on sales of products resulting from collaborative arrangements. We recognize revenues in accordance with the authoritative guidance for revenue recognition. We recognize revenue when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the seller’s price to the buyer is fixed or determinable; and (4) collectibility is reasonably assured. Product Sales, Net Hylenex Recombinant We sell Hylenex recombinant in the U.S. to wholesale pharmaceutical distributors, who sell the product to hospitals and other end-user customers. Sales to wholesalers provide for selling prices that are fixed on the date of sale, although we offer discounts to certain group purchasing organizations (“GPOs”), hospitals and government programs. The wholesalers take title to the product, bear the risk of loss of ownership and have economic substance to the inventory. Further, we have no significant obligations for future performance to generate pull-through sales. We have developed sufficient historical experience and data to reasonably estimate future returns and chargebacks of Hylenex recombinant. As a result, we recognize Hylenex recombinant product sales and related cost of product sales at the time title transfers to the wholesalers. Upon recognition of revenue from product sales of Hylenex recombinant, we record certain sales reserves and allowances as a reduction to gross revenue. These reserves and allowances include amounts for product returns (based primarily on an analysis of historical return patterns), distribution fees, prompt payment discounts, and GPO fees and other discounts and fees. We recognize product sales reserves and allowances as a reduction of product sales in the same period the related revenue is recognized. Because of the shelf life of Hylenex recombinant and our lengthy return period, there may be a significant period of time between when the product is shipped and when we issue credits on returned product. If actual product return results differ from our estimates, we will be required to make adjustments to these allowances in the future, which could have an effect on product sales revenue and earnings in the period of adjustments. Bulk rHuPH20 Subsequent to receiving marketing approval from the FDA or comparable regulatory agencies in foreign countries, sales of bulk rHuPH20 for use in collaboration commercial products are recognized as product sales when the materials have met all the specifications required for the customer’s acceptance and title and risk of loss have transferred to the customer. Following the receipt of European marketing approvals of Roche’s Herceptin SC product in August 2013 and MabThera ® SC product in March 2014 and Baxalta’s HYQVIA product in May 2013, revenue from the sales of bulk rHuPH20 for these collaboration products has been recognized as product sales. Revenues under Collaborative Agreements We have entered into license and collaboration agreements under which our collaborators obtained worldwide rights for the use of our proprietary rHuPH20 enzyme in the development and commercialization of their biologic compounds identified as targets. These agreements may also contain other elements. Pursuant to the terms of these agreements, collaborators could be required to make various payments to us for each target, including nonrefundable upfront license fees, exclusivity fees, payments based on achievement of specified milestones designated in the collaborative agreements, annual maintenance fees, reimbursements of research and development services, payments for supply of bulk rHuPH20 used by the collaborator and/or royalties on sales of products resulting from collaborative agreements. In order to account for the multiple-element arrangements, we identify the deliverables included within the collaborative agreement and evaluate which deliverables represent units of accounting. We then determine the appropriate method of revenue recognition for each unit based on the nature and timing of the delivery process. Analyzing the arrangement to identify deliverables requires the use of judgment, and each deliverable may be an obligation to deliver services, a right or license to use an asset, or another performance obligation. The deliverables under our collaborative agreements include (i) the license to our rHuPH20 technology, (ii) at the collaborator’s request, research and development services which are reimbursed at contractually determined rates, and (iii) at the collaborator’s request, supply of bulk rHuPH20 which is reimbursed at our cost plus a margin. A delivered item is considered a separate unit of accounting when the delivered item has value to the collaborator on a standalone basis based on the consideration of the relevant facts and circumstances for each arrangement. We base this determination on the collaborators’ ability to use the delivered items on their own without us supplying undelivered items, which we determine taking into consideration factors such as the research capabilities of the collaborator, the availability of research expertise in this field in the general marketplace, and the ability to procure the supply of bulk rHuPH20 from the marketplace. Arrangement consideration is allocated at the inception of the agreement to all identified units of accounting based on their relative selling price. The relative selling price for each deliverable is determined using vendor specific objective evidence (“VSOE”) of selling price or third-party evidence of selling price if VSOE does not exist. If neither VSOE nor third-party evidence of selling price exists, we use our best estimate of the selling price for the deliverable. The amount of allocable arrangement consideration is limited to amounts that are not contingent upon the delivery of additional items or meeting other specified performance conditions. The consideration received is allocated among the separate units of accounting and the applicable revenue recognition criteria are applied to each of the separate units. Changes in the allocation of the sales price between delivered and undelivered elements can impact revenue recognition but do not change the total revenue recognized under any agreement. Nonrefundable upfront license fees are recognized upon delivery of the license if facts and circumstances dictate that the license has standalone value from the undelivered items, which generally include research and development services and the manufacture of bulk rHuPH20, the relative selling price allocation of the license is equal to or exceeds the upfront license fee, persuasive evidence of an arrangement exists, our price to the collaborator is fixed or determinable and collectibility is reasonably assured. Upfront license fees are deferred if facts and circumstances dictate that the license does not have standalone value. The determination of the length of the period over which to defer revenue is subject to judgment and estimation and can have an impact on the amount of revenue recognized in a given period. When collaborators have rights to elect additional targets, the rights are assessed as to whether they represent deliverables at the inception of the arrangement. In assessing these contingent deliverables, we consider whether the right is a substantive option. We consider a right to be a substantive option if the election of the additional targets is not essential to the functionality of the other elements in the arrangement and if we are truly at risk of the right being exercised. If the right is determined to be a substantive option, we further consider whether the right is priced at a significant and incremental discount that should be accounted for as an element of the arrangement. If a right is determined to be a substantive option and is not priced at a significant and incremental discount, it is not treated as a deliverable in the arrangement and receives no allocation at the inception of the arrangement of the original arrangement consideration. The right is then accounted for when and if it is exercised. When collaborators have a right to return targets, the right is assessed as to whether the target may be returned for a refund of the purchase price, for a credit applied to amounts owed, or in exchange for other dissimilar products. We also assess if we have sufficient history to estimate the likelihood of return. If a right of return is considered to exist and we determine there is not sufficient history to estimate the likelihood of return, the consideration allocated to returnable targets is recorded as deferred revenue on the consolidated balance sheet until the right of return is exercised or expires. Certain of our collaborative agreements provide for milestone payments upon achievement of development and regulatory events and/or specified sales volumes of commercialized products by the collaborator. We account for milestone payments in accordance with the provisions of ASU No. 2010-17, Revenue Recognition - Milestone Method (“Milestone Method of Accounting”). We recognize consideration that is contingent upon the achievement of a milestone in its entirety as revenue in the period in which the milestone is achieved only if the milestone is substantive in its entirety. A milestone is considered substantive when it meets all of the following criteria: 1. The consideration is commensurate with either the entity’s performance to achieve the milestone or the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the entity’s performance to achieve the milestone; 2. The consideration relates solely to past performance; and 3. The consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. A milestone is defined as an event (i) that can only be achieved based in whole or in part on either the entity’s performance or on the occurrence of a specific outcome resulting from the entity’s performance, (ii) for which there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved, and (iii) that would result in additional payments being due to the vendor. Reimbursements of research and development services are recognized as revenue during the period in which the services are performed as long as there is persuasive evidence of an arrangement, the fee is fixed or determinable and collection of the related receivable is reasonably assured. Revenue from the manufacture of bulk rHuPH20 is recognized when the materials have met all specifications required for the collaborator’s acceptance and title and risk of loss have transferred to the collaborator. We do not directly control when any collaborator will request research and development services or supply of bulk rHuPH20; therefore, we cannot predict when we will recognize revenues in connection with research and development services and supply of bulk rHuPH20. Since we receive royalty reports 60 days after quarter end, royalty revenue from sales of collaboration products by our collaborators is recognized in the quarter following the quarter in which the corresponding sales occurred. The collaborative agreements typically provide the collaborators the right to terminate such agreement in whole or on a product-by-product or target-by-target basis at any time upon 30 to 90 days prior written notice to us. There are no performance, cancellation, termination or refund provisions in any of our collaborative agreements that contain material financial consequences to us.
Cost of Product Sales, Policy [Policy Text Block]	Cost of Product Sales Cost of product sales consists primarily of raw materials, third-party manufacturing costs, fill and finish costs, freight costs, internal costs and manufacturing overhead associated with the production of Hylenex recombinant and bulk rHuPH20 for use in approved collaboration products. Cost of product sales also consists of the write-down of excess, dated and obsolete inventories and the write-off of inventories that do not meet certain product specifications, if any.
Research and Development Expenses	Research and Development Expenses Research and development expenses include salaries and benefits, facilities and other overhead expenses, external clinical trial expenses, research related manufacturing services, contract services and other outside expenses. Research and development expenses are charged to operating expenses as incurred when these expenditures relate to our research and development efforts and have no alternative future uses. After receiving approval from the FDA or comparable regulatory agencies in foreign countries for a product, costs related to purchases and manufacturing of bulk rHuPH20 for such product are capitalized as inventory. The manufacturing costs of bulk rHuPH20 for the collaboration products, Herceptin SC, MabThera SC (RITUXAN HYCELA™ in the U.S.) and HYQVIA, incurred after the receipt of marketing approvals are capitalized as inventory. We are obligated to make upfront payments upon execution of certain research and development agreements. Advance payments, including nonrefundable amounts, for goods or services that will be used or rendered for future research and development activities are deferred. Such amounts are recognized as expense as the related goods are delivered or the related services are performed or such time when we do not expect the goods to be delivered or services to be performed. Milestone payments that we make in connection with in-licensed technology for a particular research and development project that have no alternative future uses (in other research and development projects or otherwise) and therefore no separate economic value are expensed as research and development costs at the time the costs are incurred.
Clinical Trial Expenses	Clinical Trial Expenses We make payments in connection with our clinical trials under contracts with contract research organizations that support conducting and managing clinical trials. The financial terms of these agreements are subject to negotiation and vary from contract to contract and may result in uneven payment flows. Generally, these agreements set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. A portion of our obligation to make payments under these contracts depends on factors such as the successful enrollment or treatment of patients or the completion of other clinical trial milestones. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly on a prospective basis. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain.
Share-Based Compensation	Share-Based Compensation We record compensation expense associated with stock options, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and RSUs with performance conditions (“PRSUs”) in accordance with the authoritative guidance for stock-based compensation. The cost of employee services received in exchange for an award of an equity instrument is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense on a straight-line basis over the requisite service period of the award. Share-based compensation expense for an award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized and any previously recognized compensation expense is reversed. Forfeitures are recognized as a reduction of share-based compensation expense as they occur.
Income Taxes	Income Taxes We provide for income taxes using the liability method. Under this method, deferred income tax assets and liabilities are determined based on the differences between the financial statement carrying amounts of existing assets and liabilities at each year end and their respective tax bases and are measured using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Significant judgment is required by management to determine our provision for income taxes, our deferred tax assets and liabilities, and the valuation allowance to record against our net deferred tax assets, which are based on complex and evolving tax regulations throughout the world. Deferred tax assets and other tax benefits are recorded when it is more likely than not that the position will be sustained upon audit. While we have begun to utilize certain of our net operating losses, we have not yet established a track record of profitability. Accordingly, valuation allowances have been recorded to reduce our net deferred tax assets to zero , with the exception of the alternative minimum tax ("AMT") credit carryover. Under the Tax Cuts and Jobs Act enacted in December 2017, the AMT credit carryover will either be utilized, or if unutilized fully refunded in 2022. For all other deferred tax assets the valuation allowance will reduce the net value to zero until such time as we can demonstrate an ability to realize them.
Net Income (Loss) Per Share	Net Income (Loss) Per Share Basic net income (loss) per common share is computed by dividing net income (loss) for the period by the weighted average number of common shares outstanding during the period, without consideration for common stock equivalents. Outstanding stock options, unvested RSAs, unvested RSUs and unvested PRSUs are considered common stock equivalents and are only included in the calculation of diluted earnings per common share when net income is reported and their effect is dilutive.
Segment Information	Segment Information We operate our business in one segment, which includes all activities related to the research, development and commercialization of our proprietary enzymes. This segment also includes revenues and expenses related to (i) research and development and bulk rHuPH20 manufacturing activities conducted under our collaborative agreements with third parties and (ii) product sales of Hylenex recombinant. The chief operating decision-maker reviews the operating results on an aggregate basis and manages the operations as a single operating segment.
Adoption and Pending Adoption of Recent Accounting Pronouncements	Adoption and Pending Adoption of Recent Accounting Pronouncements The following table provides a brief description of recently issued accounting standards, those adopted in the current period and those not yet adopted: Standard Description Effective Date Effect on the Financial Statements or Other Significant Matters In July 2015, the FASB issued ASU 2015-11, Inventory: Simplifying the Measurement of Inventory. The new guidance requires that for entities that measure inventory using the first-in, first-out method, inventory should be measured at the lower of cost or net realizable value. Topic 330, Inventory, currently requires an entity to measure inventory at the lower of cost or market. Market could be replacement cost, net realizable value, or net realizable value less an approximate normal profit margin. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. January 1, 2017. The adoption did not have a material impact on our consolidated financial position or results of operations. In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740), Balance Sheet Classification of Deferred Tax Assets The amendments in this update simplify the presentation of deferred income taxes by requiring that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. January 1, 2017 The adoption of this guidance did not have a significant impact on the Company’s financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments. Current U.S. GAAP either is unclear or does not include specific guidance on the eight cash flow classification issues included in ASU 2016-15. The new guidance is an improvement to U.S. GAAP and is intended to reduce the current and potential future diversity in practice. ASU 2016-18 provides additional classification guidance for restricted cash, which requires that restricted cash be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. January 1, 2018. We have elected to early adopt as of January 1, 2017. Cash and cash equivalents at the beginning-of-period and end-of-period total amounts in the Consolidated Statements of Cash Flows have been adjusted to include $0.5 million of restricted cash for each of the periods presented. Standard Description Effective Date Effect on the Financial Statements or Other Significant Matters In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall; Recognition and Measurement of Financial Assets and Financial Liabilities. The new guidance supersedes the guidance to classify equity securities with readily determinable fair values into different categories (that is, trading or available-for-sale) and requires equity securities to be measured at fair value with changes in the fair value recognized through net income. The new guidance requires public business entities that are required to disclose fair value of financial instruments measured at amortized cost on the balance sheet to measure that fair value using the exit price notion consistent with Topic 820, Fair Value Measurement. January 1, 2018. We currently do not hold equity securities, and we are evaluating the effect the updated standard will have on our consolidated financial statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). In March, April, May and December 2016, the FASB issued additional guidance related to Topic 606. The new standard will supersede nearly all existing revenue recognition guidance. Under Topic 606, an entity is required to recognize revenue upon transfer of promised goods or services to customers in an amount that reflects the expected consideration to be received in exchange for those goods or services. Topic 606 defines a five-step process in order to achieve this core principle, which may require the use of judgment and estimates, and also requires expanded qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, including significant judgments and estimates used. The new standard also defines accounting for certain costs related to origination and fulfillment of contracts with customers, including whether such costs should be capitalized. The new standard permits adoption either by using (i) a full retrospective approach for all periods presented in the period of adoption or (ii) a modified retrospective approach where the new standard is applied in the financial statements starting with the year of adoption. Under both approaches, cumulative impact of the adoption is reflected as an adjustment to retained earnings (accumulated equity (deficit)) as of the earliest date presented in accordance with the new standard. January 1, 2018. Early adoption is permitted. We plan to implement the new guidance on January 1, 2018 using the modified retrospective approach. We have substantially completed our evaluation of the effect that the updated standard will have on our consolidated financial statements and related disclosures. Adoption of the new guidance will impact the timing of recognition of payments related to certain of our license and collaboration agreements (1) and the timing of recognition of our sales-based royalties. (2) This standard will have a material impact on our consolidated financial statements. Standard Description Effective Date Effect on the Financial Statements or Other Significant Matters In February 2016, the FASB issued ASU 2016-02, Leases. The new guidance requires lessees to recognize assets and liabilities for most leases and provides enhanced disclosures. January 1, 2019. Early adoption is permitted. We are currently evaluating the effect the updated standard will have on our consolidated financial statements and related disclosures and do not intend to early adopt. We anticipate recognition of additional assets and corresponding liabilities related to our leases on our consolidated balance sheet. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments The standard amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses for most financial assets and certain other instruments that aren’t measured at fair value through net income. January 1, 2020 The Company does not believe the adoption will have a material impact on our consolidated financial position or results of operations.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	The following table indicates the percentage of total revenues in excess of 10% with any single customer: Year Ended December 31, 2017 2016 2015 Roche 38% 63% 42% BMS 32% — — Alexion 13% — — Baxalta 7% 12% 7% Lilly — 6% 19% AbbVie — 4% 17% We attribute revenues under collaborative agreements, including royalties, to the individual countries where the collaborator is headquartered. We attribute revenues from product sales to the individual countries to which the product is shipped. Worldwide revenues from external customers are summarized by geographic location in the following table (in thousands): Year Ended December 31, 2017 2016 2015 United States $ 196,274 $ 52,292 $ 77,149 Switzerland 119,136 93,067 57,136 All other foreign 1,203 1,332 772 Total revenues $ 316,613 $ 146,691 $ 135,057
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	A reconciliation of the numerators and the denominators of the basic and diluted net income (loss) per common share computations is as follows (in thousands, except per share amounts): Year Ended December 31, 2017 2016 2015 Numerator: Net income (loss) $ 62,971 $ (103,023 ) $ (32,231 ) Denominator: Weighted average common shares outstanding for basic 136,419 127,964 126,704 Net effect of dilutive common stock equivalents 2,649 — — Weighted average common shares outstanding for diluted 139,068 127,964 126,704 Net income (loss) per share: Basic $ 0.46 $ (0.81 ) $ (0.25 ) Diluted $ 0.45 $ (0.81 ) $ (0.25 )

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Available-for-sale marketable securities	Available-for-sale marketable securities consisted of the following (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate debt securities $ 117,427 $ — $ (235 ) $ 117,192 U.S. Treasury securities 66,601 — (201 ) 66,400 Commercial paper 116,882 — — 116,882 $ 300,910 $ — $ (436 ) $ 300,474 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate debt securities $ 40,221 $ 1 $ (15 ) $ 40,207 U.S. Treasury securities 94,002 24 (16 ) 94,010 Commercial paper 4,000 — — 4,000 $ 138,223 $ 25 $ (31 ) $ 138,217
Investments Classified by Contractual Maturity Date [Table Text Block]	Contractual maturities of available-for-sale debt securities are as follows (in thousands): December 31, 2017 December 31, 2016 Estimated Fair Value Due within one year $ 213,426 $ 132,221 After one but within five years 87,048 5,996 $ 300,474 $ 138,217
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	The following table summarizes, by major security type, our cash equivalents and available-for-sale marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands): December 31, 2017 December 31, 2016 Level 1 Level 2 Total estimated fair value Level 1 Level 2 Total estimated fair value Cash equivalents: Money market funds $ 142,091 $ — $ 142,091 $ 60,916 $ — $ 60,916 Commercial paper — 15,700 15,700 — — — Available-for-sale marketable securities: Corporate debt securities — 117,192 117,192 — 40,207 40,207 U.S. Treasury securities 66,400 — 66,400 94,010 — 94,010 Commercial paper — 116,882 116,882 — 4,000 4,000 $ 208,491 $ 249,774 $ 458,265 $ 154,926 $ 44,207 $ 199,133

Collaborative Agreements Collab

Collaborative Agreements Collaborative Agreements (Tables)	12 Months Ended
	Dec. 31, 2017
Roche [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]	As of December 31, 2017 Upfront license fee payment for the application of rHuPH20 to the initial exclusive targets $ 20,000 Election of additional exclusive targets and annual license maintenance fees for the right to designate the remaining targets as exclusive targets 23,000 Clinical development milestone payments 13,000 Regulatory milestone payments 8,000 Sales-based milestone payments 22,000 Total payments received $ 86,000
Baxalta [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]	As of December 31, 2017 Upfront license fee payment for the application of rHuPH20 to the initial exclusive target $ 10,000 Regulatory milestone payments 3,000 Sales-based milestone payments 9,000 Total payments received $ 22,000
Other collaborators [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]	As of December 31, 2017 Alexion Collaboration $ 40,000 BMS Collaboration 105,000 Lilly Collaboration 33,000 AbbVie Collaboration 29,000 Janssen Collaboration 30,250 Pfizer Collaboration 16,500 Total payments received $ 253,750
License Fees [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]	Based on the results of our analysis, we allocated the following amounts to the license fee deliverable under the arrangement (in thousands): Consideration allocated to license fees: Alexion Collaboration $ 40,000 BMS Collaboration 101,400 Lilly Collaboration 33,000 AbbVie Collaboration 23,000 Janssen Collaboration 15,250 Pfizer Collaboration 12,500 Total consideration allocated to license fees $ 225,150

Certain Balance Sheet Items (Ta

Certain Balance Sheet Items (Tables)	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Summary of Accounts Receivable	Accounts receivable, net consisted of the following (in thousands): December 31, December 31, Accounts receivable from product sales to collaborators $ 18,475 $ 7,854 Accounts receivable from revenues under collaborative agreements 2,142 6,151 Accounts receivable from other product sales 2,075 2,234 Subtotal 22,692 16,239 Allowance for distribution fees and discounts (559 ) (559 ) Total accounts receivable, net $ 22,133 $ 15,680
Summary of Inventories	Inventories consisted of the following (in thousands): December 31, December 31, Raw materials $ 377 $ 761 Work-in-process 2,131 12,850 Finished goods 2,638 1,012 Total inventories $ 5,146 $ 14,623
Summary of Prepaid Expenses and Other Assets	Prepaid expenses and other assets consisted of the following (in thousands): December 31, December 31, Prepaid manufacturing expenses $ 2,337 $ 9,663 Prepaid research and development expenses 7,793 8,613 Other prepaid expenses 2,585 1,661 Other assets 6,717 1,530 Total prepaid expenses and other assets 19,432 21,467 Less long-term portion 5,553 219 Total prepaid expenses and other assets, current $ 13,879 $ 21,248
Summary of Property and Equipment	Property and equipment, net consisted of the following (in thousands): December 31, December 31, Research equipment $ 10,970 $ 10,479 Computer and office equipment 3,725 3,373 Leasehold improvements 2,715 2,331 Subtotal 17,410 16,183 Accumulated depreciation and amortization (13,890 ) (11,919 ) Property and equipment, net $ 3,520 $ 4,264
Summary of Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, December 31, Accrued outsourced research and development expenses $ 18,757 $ 9,522 Accrued compensation and payroll taxes 13,384 11,539 Accrued outsourced manufacturing expenses 2,504 3,225 Other accrued expenses 5,396 4,552 Total accrued expenses 40,041 28,838 Less long-term portion 440 17 Total accrued expenses, current $ 39,601 $ 28,821
Summary of Deferred Revenue	Deferred revenue consisted of the following (in thousands): December 31, December 31, Collaborative agreements License fees and event-based payments: Roche $ 39,379 $ 35,709 Other 15,999 8,209 55,378 43,918 Reimbursement for research and development services — 700 Product sales 5,487 — Total deferred revenue 60,865 44,618 Less current portion 6,568 4,793 Deferred revenue, net of current portion $ 54,297 $ 39,825

Long-Term Debt, Net Debt Disclo

Long-Term Debt, Net Debt Disclosure (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt [Table Text Block]	Future maturities and interest payments of long-term debt as of December 31, 2017 , are as follows (in thousands): 2018 $ 94,125 2019 105,758 2020 27,311 2021 4,755 2022 — Total minimum payments 231,949 Less amount representing interest (26,792 ) Gross balance of long-term debt 205,157 Less unamortized debt discount (2,806 ) Present value of long-term debt 202,351 Less current portion of long-term debt (77,211 ) Long-term debt, less current portion and unamortized debt discount $ 125,140

Share-based Compensation (Table

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	Total share-based compensation expense related to share-based awards was comprised of the following (in thousands): Year Ended December 31, 2017 2016 2015 Research and development $ 13,080 $ 11,470 $ 9,795 Selling, general and administrative 17,590 14,115 11,043 Share-based compensation expense $ 30,670 $ 25,585 $ 20,838
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	Share-based compensation expense by type of share-based award (in thousands): Year Ended December 31, 2017 2016 2015 Stock options $ 19,583 $ 16,544 $ 11,145 RSAs, RSUs and PRSUs 11,087 9,041 9,693 $ 30,670 $ 25,585 $ 20,838
Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block]	Total unrecognized estimated compensation cost by type of award and the weighted-average remaining requisite service period over which such expense is expected to be recognized (in thousands, unless otherwise noted): December 31, 2017 Unrecognized Expense Remaining Weighted-Average Recognition Period (years) Stock options $ 36,914 2.4 RSAs $ 4,610 1.6 RSUs $ 15,965 2.6
Share-based Compensation, Stock Options, Activity [Table Text Block]	A summary of our stock option award activity as of and for the years ended December 31, 2017, 2016 and 2015 is as follows: Shares Weighted Weighted Aggregate Outstanding at January 1, 2015 6,353,892 $9.18 Granted 3,973,604 $16.26 Exercised (1,926,368 ) $7.49 Canceled/forfeited (407,936 ) $10.64 Outstanding at December 31, 2015 7,993,192 $13.03 Granted 4,466,306 $9.03 Exercised (413,248 ) $6.88 Canceled/forfeited (955,054 ) $12.42 Outstanding at December 31, 2016 11,091,196 $11.70 Granted 2,717,614 $12.60 Exercised (1,514,826 ) $9.24 Canceled/forfeited (1,185,518 ) $11.89 Outstanding at December 31, 2017 11,108,466 $12.24 7.0 $90.8 million Vested and expected to vest at December 31, 2017 11,108,466 $12.24 7.0 $90.8 million Exercisable at December 31, 2017 5,493,802 $12.31 6.1 $44.7 million
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The assumptions used in the Black-Scholes model were as follows: Year Ended December 31, 2017 2016 2015 Expected volatility 69.8-71.7% 67.5-71.9% 66.2-67.4% Average expected term (in years) 5.6 5.4 5.6 Risk-free interest rate 1.73-2.13% 1.00-1.90% 1.34-1.92% Expected dividend yield — — —
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	The following table summarizes our RSA activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Unvested at January 1, 2015 1,158,451 $10.26 Granted 515,695 $15.00 Vested (721,990 ) $10.11 Forfeited (140,676 ) $11.84 Unvested at December 31, 2015 811,480 $13.13 Granted 968,652 $8.41 Vested (296,831 ) $12.76 Forfeited (180,198 ) $10.33 Unvested at December 31, 2016 1,303,103 $10.09 Granted 98,945 $14.15 Vested (514,613 ) $10.23 Forfeited (108,485 ) $9.62 Unvested at December 31, 2017 778,950 $10.59
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	The following table summarizes our RSU activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Weighted Aggregate Unvested at January 1, 2015 462,322 $11.12 Granted 422,492 $14.75 Vested (134,088 ) $10.93 Forfeited (84,512 ) $10.86 Outstanding at December 31, 2015 666,214 $13.49 Granted 796,582 $8.17 Vested (218,279 ) $12.74 Forfeited (77,948 ) $10.99 Outstanding at December 31, 2016 1,166,569 $10.16 Granted 1,378,273 $12.13 Vested (378,406 ) $10.48 Forfeited (251,261 ) $11.11 Outstanding at December 31, 2017 1,915,175 $11.39 1.4 $38.8 million
Schedule of Nonvested Performance-based Units Activity [Table Text Block]	The following table summarizes our PRSU activity during the years ended December 31, 2017, 2016 and 2015 : Number of Weighted Average Grant Date Fair Value Outstanding at January 1, 2015 431,238 $8.91 Granted 118,209 $11.19 Vested (83,380 ) $9.48 Forfeited (156,360 ) $9.21 Outstanding at December 31, 2015 309,707 $9.48 Granted — — Vested (30,037 ) $9.49 Forfeited (79,415 ) $9.44 Outstanding at December 31, 2016 200,255 $9.49 Granted — — Vested — — Forfeited (200,255 ) $9.49 Outstanding at December 31, 2017 — —

Commitments and Contingencies C

Commitments and Contingencies Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Approximate annual future minimum operating lease payments as of December 31, 2017 are as follows (in thousands): Year: Operating 2018 $ 2,415 2019 2,785 2020 2,824 2021 2,470 2022 2,506 Total minimum lease payments $ 13,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	Total income (loss) before income taxes summarized by region were as follows (in thousands): Year Ended December 31, 2017 2016 2015 United States $ 160,938 $ 6,384 $ 11,724 Foreign (99,328 ) (108,245 ) (43,955 ) Net income (loss) before income taxes $ 61,610 $ (101,861 ) $ (32,231 )
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Significant components of our net deferred tax assets/(liabilities) were as follows (in thousands). December 31, 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 32,630 $ 103,296 Deferred revenue 8,815 15,354 Research and development and orphan drug credits 75,224 73,701 Share-based compensation 7,423 8,844 Alternative minimum tax credit 5,532 1,494 Other, net 2,270 1,021 131,894 203,710 Valuation allowance for deferred tax assets (126,189 ) (203,370 ) Deferred tax assets, net of valuation 5,705 340 Deferred tax liabilities: Depreciation (173 ) (340 ) Total deferred tax liabilities (173 ) (340 ) Net deferred tax asset (liability) $ 5,532 $ —
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	Income tax expense was comprised of the following components (in thousands): Year Ended December 31, 2017 2016 2015 Current - federal $ 4,051 $ 1,145 $ — Current - state 120 17 — Deferred - federal (5,532 ) — — Deferred - state — — — $ (1,361 ) $ 1,162 $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The provision for income taxes on earnings subject to income taxes differs from the statutory federal income tax rate due to the following (in thousands): Year Ended December 31, 2017 2016 2015 Federal income tax expense (benefit) at 34% $ 20,947 $ (34,633 ) $ (10,959 ) State income tax benefit, net of federal income tax impact 930 (653 ) 5,524 (Decrease) increase in valuation allowance (77,181 ) 11,252 4,045 Enactment of the Tax Cuts and Jobs Act 17,132 — — Foreign income subject to tax at other than federal statutory rate 33,674 36,803 14,945 Shared-based compensation 525 3,735 (4,990 ) Non-deductible expenses and other 5,779 698 6,457 Research and development credits, net 4,162 (1,084 ) (3,861 ) Orphan drug credits, net of federal add back (7,329 ) (14,956 ) (11,161 ) $ (1,361 ) $ 1,162 $ —
Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block]	The following table summarizes the activity related to our unrecognized tax benefits (in thousands): Year Ended December 31, 2017 2016 2015 Gross unrecognized tax benefits at beginning of period $ 12,799 $ 4,898 $ — Increases in tax positions for prior years — 5,615 — Decreases in tax positions for prior years (2,518 ) (4,898 ) — Increases in tax positions for current year 4,147 7,184 4,898 Gross unrecognized tax benefits at end of period $ 14,428 $ 12,799 $ 4,898
Summary of Operating Loss Carryforwards [Table Text Block]	The following table shows key expiration dates of the federal and California net operating loss carryforwards (in thousands): Expires in: Net Operating Loss 2018 2021 and beyond 2028 and beyond Federal $ 88,516 — $ 88,516 — California $ 243,080 — — $ 243,080

Summary of Unaudited Quarterl30

Summary of Unaudited Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Table Text Block]	The following is a summary of our unaudited quarterly results for the years ended December 31, 2017 and 2016 (in thousands): Quarter Ended 2017 (Unaudited): March 31, June 30, September 30, December 31, Total revenues (1) (2) $ 29,568 $ 33,750 $ 63,731 $ 189,564 Gross profit on product sales $ 3,890 $ 4,992 $ 5,257 $ 5,105 Total operating expenses $ 57,094 $ 59,228 $ 55,654 $ 63,635 Net income (loss) $ (32,897 ) $ (30,763 ) $ 2,749 $ 123,882 Net income (loss) per share: Basic $ (0.26 ) $ (0.23 ) $ 0.02 $ 0.87 Diluted $ (0.26 ) $ (0.23 ) $ 0.02 $ 0.85 Shares used in computing net income (loss) per share: Basic 128,615 134,013 141,190 141,718 Diluted 128,615 134,013 143,236 145,633 Quarter Ended 2016 (Unaudited): March 31, June 30, September 30, December 31, Total revenues $ 42,499 $ 33,336 $ 31,853 $ 39,003 Gross profit on product sales $ 5,178 $ 5,391 $ 4,197 $ 5,420 Total operating expenses $ 58,668 $ 55,059 $ 54,596 $ 61,578 Net loss $ (19,816 ) $ (26,875 ) $ (28,946 ) $ (27,386 ) Net loss per share, basic and diluted $ (0.16 ) $ (0.21 ) $ (0.23 ) $ (0.21 ) Shares used in computing basic and diluted net loss per share 127,615 127,958 128,154 128,185 _______________ (1) Revenues for the quarter ended December 31, 2017 included $101.4 million , $40.0 million and $15.0 million in revenue under collaborative arrangements from BMS, Alexion and Janssen, respectively. (2) Revenues for the quarter ended September 30, 2017 included $30.0 million in revenue under collaborative arrangements from the 2017 Roche Collaboration.

Summary of Significant Accoun31

Summary of Significant Accounting Policies Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Restricted Cash and Investments, Current [Abstract]
Restricted cash	$ 500	$ 500

Summary of Significant Accoun32

Summary of Significant Accounting Policies Concentrations of Credit Risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Concentration Risk [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 0
Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Revenue, Net	$ 316,613	$ 146,691	$ 135,057
Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	10.00%
UNITED STATES | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Revenue, Net	$ 196,274	52,292	77,149
SWITZERLAND | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Revenue, Net	119,136	93,067	57,136
All other foreign [Member] | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Revenue, Net	1,203	1,332	$ 772
GERMANY
Concentration Risk [Line Items]
Long-Lived Assets	$ 100	$ 100
Roche [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	38.00%	63.00%	42.00%
BMS [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	32.00%	0.00%	0.00%
Alexion [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	13.00%	0.00%	0.00%
Baxalta [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	7.00%	12.00%	7.00%
Lilly [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	6.00%	19.00%
AbbVie [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	0.00%	4.00%	17.00%
Roche and Baxalta [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage (instant date)	86.00%	81.00%
Bulk formulation [Member] | Accounts Payable [Member] | Supplier Concentration Risk [Member]
Concentration Risk [Line Items]
Number of manufacturers	2
Concentration Risk, Percentage (instant date)	4.00%	13.00%
Hylenex Recombinant [Member] | Accounts Payable [Member] | Supplier Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage (instant date)	1.00%	2.00%

Summary of Significant Accoun33

Summary of Significant Accounting Policies Accounts Receivable (Details) $ in Thousands	Dec. 31, 2017USD ($)
Accounting Policies [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$ 0

Summary of Significant Accoun34

Summary of Significant Accounting Policies Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory [Line Items]
Inventory, Net	$ 5,146	$ 14,623
Hylenex Recombinant [Member]
Inventory [Line Items]
Inventory, Net	2,900	2,300
bulk rHuPH20
Inventory [Line Items]
Inventory, Net	$ 2,200	$ 12,300

Summary of Significant Accoun35

Summary of Significant Accounting Policies Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Property, Plant and Equipment, Useful Life	3 years

Summary of Significant Accoun36

Summary of Significant Accounting Policies Impairment of Long-Lived Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 0

Summary of Significant Accoun37

Summary of Significant Accounting Policies Revenue recognition (Details)	12 Months Ended
	Dec. 31, 2017
Collaborative agreements termination notification
Notification period for termination	90 days
Period prior to expiration
Collaborative agreements termination notification
Notification period for termination	30 days
Period after expiration
Collaborative agreements termination notification
Notification period for termination	90 days

Summary of Significant Accoun38

Summary of Significant Accounting Policies Research and development (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
In-license technologies [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development, in-line technologies	$ 0

Summary of Significant Accoun39

Summary of Significant Accounting Policies Income tax (Details)	Dec. 31, 2017USD ($)
Income Tax Disclosure [Abstract]
Deferred tax asset excluding amount for AMT	$ 0

Summary of Significant Accoun40

Summary of Significant Accounting Policies Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss Per Share Disclosure [Line Items]
Net income (loss)	$ 123,882	$ 2,749	$ (30,763)	$ (32,897)	$ (27,386)	$ (28,946)	$ (26,875)	$ (19,816)	$ 62,971	$ (103,023)	$ (32,231)
Weighted Average Number of Shares Outstanding, Basic	141,718	141,190	134,013	128,615					136,419	127,964	126,704
Shares excluded from calculation of diluted net loss, amount									2,649	0	0
Weighted Average Number of Shares Outstanding, Diluted	145,633	143,236	134,013	128,615					139,068	127,964	126,704
Earnings Per Share, Basic	$ 0.87	$ 0.02	$ (0.23)	$ (0.26)					$ 0.46	$ (0.81)	$ (0.25)
Earnings Per Share, Diluted	$ 0.85	$ 0.02	$ (0.23)	$ (0.26)					$ 0.45	$ (0.81)	$ (0.25)
Net loss per share (Textuals) [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									7,100	13,800	9,800

Summary of Significant Accoun41

Summary of Significant Accounting Policies Segment information (Details)	12 Months Ended
	Dec. 31, 2017Segment
Segment Reporting [Abstract]
Number of Operating Segments	1

Summary of Significant Accoun42

Summary of Significant Accounting Policies Adoption of Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Reclassification of restricted cash	$ 500	$ 500	$ 500
Revenue, amortization of license payments	4,100
Deferred Revenue Relating To Upfront Payment License Fees	51,800
Hypothetical License Revenue under ASC 606	198,400
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				$ 19,400
Royalty Revenue	63,507	$ 50,984	$ 30,975
Hypothetical Royalty Revenue under ASC 606	$ 68,900

Fair Value Measurement (Details

Fair Value Measurement (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities
Amortized cost	$ 300,910	$ 138,223
Gross Unrealized Gains	0	25
Gross Unrealized Losses	(436)	(31)
Estimated fair value	300,474	138,217
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities
Amortized cost	117,427	40,221
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(235)	(15)
Estimated fair value	117,192	40,207
US Treasury Securities [Member]
Schedule of Available-for-sale Securities
Amortized cost	66,601	94,002
Gross Unrealized Gains	0	24
Gross Unrealized Losses	(201)	(16)
Estimated fair value	66,400	94,010
Commercial Paper [Member]
Schedule of Available-for-sale Securities
Amortized cost	116,882	4,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated fair value	$ 116,882	$ 4,000

Fair Value Measurement Textuals

Fair Value Measurement Textuals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Fair Value Disclosures [Abstract]
Number of available-for-sale securities in unrealized loss position, less than one year	28
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 183.6
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0.4
Other than Temporary Impairment Losses, Marketable Securities	$ 0

Fair Value Measurement Maturiti

Fair Value Measurement Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Due within one year	$ 213,426	$ 132,221
After one but within five years	87,048	5,996
Available-for-sale Securities	$ 300,474	$ 138,217

Fair Value Measurement Fair Val

Fair Value Measurement Fair Value Measures (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	$ 300,474	$ 138,217
Fair Value Disclosure	458,265	199,133
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0	0
Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash Equivalents	142,091	60,916
Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash Equivalents	15,700	0
Available-for-sale Securities	116,882	4,000
Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	117,192	40,207
US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	66,400	94,010
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure	208,491	154,926
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash Equivalents	142,091	60,916
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	66,400	94,010
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure	249,774	44,207
Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash Equivalents	15,700	0
Available-for-sale Securities	116,882	4,000
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	117,192	40,207
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Level 3	$ 0	$ 0

Collaborative Agreements Coll47

Collaborative Agreements Collaborative Agreements Textuals (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Compound	Dec. 31, 2016USD ($)Compound	Dec. 31, 2015USD ($)
Collaborative Agreements Terms
Number of targets optional, additional fees contingent	2
Notification period for termination	90 days
Deferred Revenue (Textual) [Abstract]
Deferred revenue relating to upfront payment license fees and annual maintenance fees | $	$ 60,865	$ 44,618
Collaborative Agreements (Textual)
Additional maximum proceeds receivable from collaborators of license and collaborative agreement upon achievement of clinical development milestones for elected targets | $	62,500
Sales-based payment to be received upon the first commercial sale | $	12,000
Roche [Member]
Deferred Revenue (Textual) [Abstract]
Deferred revenue relating to upfront payment license fees and annual maintenance fees | $	39,379	35,709
Baxalta [Member]
Deferred Revenue (Textual) [Abstract]
Deferred revenue relating to upfront payment license fees and annual maintenance fees | $	$ 12,400	8,200
Roche [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	13
Number of exclusive right targets	3
Number of additional targets, optional	10
Number of targets elected	8
Number of targets elected, additional exclusive targets	2
Collaborative agreement target selection period	10 years
Duration of royalty receivable	10 years
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 20,000
Collaborative Agreements (Textual)
Deferred revenue, revenue recognized | $	$ 3,300	3,300	$ 3,300
2017 Roche [Member]
Collaborative Agreements Terms
Number of targets elected, additional exclusive targets	1
Duration of royalty receivable	10 years
Notification period for termination	90 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 30,000
Baxalta [Member]
Collaborative Agreements Terms
Duration of royalty receivable	10 years
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 10,000
Collaborative Agreements (Textual)
Deferred revenue, revenue recognized | $	$ 800	$ 800	800
Alexion [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	4
Number of additional targets, optional	2
Number of targets elected, additional exclusive targets	2
Duration of royalty receivable	10 years
Notification period for termination	90 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 40,000
BMS [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	11
Number of targets elected, additional semi-exclusive targets	1
Duration of royalty receivable	10 years
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 101,400
Lilly [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	5
Number of additional targets, optional	2
Number of targets elected, additional exclusive targets	2
Number of targets elected, additional semi-exclusive targets	1
Duration of royalty receivable	10 years
Notification period for termination	60 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 33,000
AbbVie [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	9
Number of additional targets, optional	8
Number of targets elected	1
Duration of royalty receivable	10 years
Notification period for termination	90 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 23,000
Janssen [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	5
Number of additional targets, optional	4
Number of targets elected	1
Duration of royalty receivable	10 years
Notification period for termination	90 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 15,250
Pfizer [Member]
Collaborative Agreements Terms
Number of product compound combinations licensed to develop	6
Number of additional targets, optional	3
Number of targets elected	5
Number of Returned Targets		2
Duration of royalty receivable	10 years
Notification period for termination	30 days
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	$ 12,500
Other collaborators [Member]
Deferred Revenue (Textual) [Abstract]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement | $	225,150
Collaborative Agreements (Textual)
Revenue Recognition, Event-based or Milestone, Revenue Recognized | $	$ 15,000	$ 6,000	$ 1,000

Collaborative Agreements Coll48

Collaborative Agreements Collaborative Agreements tables (Details) $ in Thousands	Dec. 31, 2017USD ($)
Roche [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	$ 20,000
Additional Exclusive Targets And Annual License Maintenance Fees	23,000
Clinical development milestone payments	13,000
Regulatory milestone payments	8,000
Sales-based milestone payments	22,000
Total Proceeds from Partner of License and Collaborative Agreement	86,000
Baxalta [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	10,000
Regulatory milestone payments	3,000
Sales-based milestone payments	9,000
Total Proceeds from Partner of License and Collaborative Agreement	22,000
Lilly [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	33,000
Total Proceeds from Partner of License and Collaborative Agreement	33,000
AbbVie [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	23,000
Total Proceeds from Partner of License and Collaborative Agreement	29,000
Janssen [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	15,250
Total Proceeds from Partner of License and Collaborative Agreement	30,250
Pfizer [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	12,500
Total Proceeds from Partner of License and Collaborative Agreement	16,500
BMS [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	101,400
Total Proceeds from Partner of License and Collaborative Agreement	105,000
Alexion [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	40,000
Total Proceeds from Partner of License and Collaborative Agreement	40,000
Other collaborators [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Nonrefundable Upfront License Fee Payment Received Under Collaborative Agreement	225,150
Total Proceeds from Partner of License and Collaborative Agreement	$ 253,750

Certain Balance Sheet Items - A

Certain Balance Sheet Items - Accounts receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Accounts receivable from product sales to collaborators	$ 18,475	$ 7,854
Accounts receivable from revenues under collaborative agreements	2,142	6,151
Accounts receivable from other product sales	2,075	2,234
Accounts receivable, gross	22,692	16,239
Allowance for distribution fees and discounts	(559)	(559)
Total accounts receivable, net	$ 22,133	$ 15,680

Certain Balance Sheet Items - I

Certain Balance Sheet Items - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventory, Raw Materials	$ 377	$ 761
Inventory, Work in Process	2,131	12,850
Inventory, Finished Goods	2,638	1,012
Summary of Inventories
Total inventories	$ 5,146	$ 14,623

Certain Balance Sheet Items - P

Certain Balance Sheet Items - Prepaid expenses and other assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid manufacturing expenses	$ 2,337	$ 9,663
Prepaid research and development expenses	7,793	8,613
Other prepaid expenses	2,585	1,661
Other assets	6,717	1,530
Total prepaid expense and other assets	19,432	21,467
Less long-term portion	5,553	219
Total prepaid expense and other assets, current	$ 13,879	$ 21,248

Certain Balance Sheet Items -52

Certain Balance Sheet Items - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property and equipment, gross	$ 17,410	$ 16,183
Accumulated depreciation and amortization	(13,890)	(11,919)
Property and equipment, net	3,520	4,264
Research equipment
Property and equipment, gross	10,970	10,479
Computer and office equipment
Property and equipment, gross	3,725	3,373
Leasehold improvements
Property and equipment, gross	$ 2,715	$ 2,331

Certain Balance Sheet Items -53

Certain Balance Sheet Items - Property and Equipment, Net (Textuals) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation and amortization
Depreciation and amortization	$ 2,161	$ 2,410	$ 1,677

Certain Balance Sheet Items -54

Certain Balance Sheet Items - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of Accrued Expenses
Accrued outsourced research and development	$ 18,757	$ 9,522
Accrued compensation and payroll taxes	13,384	11,539
Accrued outsourced manufacturing expenses	2,504	3,225
Other accrued expenses	5,396	4,552
Total accrued expenses	40,041	28,838
Less long-term portion	440	17
Total accrued expenses, current	$ 39,601	$ 28,821

Certain Balance Sheet Items - D

Certain Balance Sheet Items - Deferred Revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred revenue
Total deferred revenue	$ 60,865	$ 44,618
Less current portion	6,568	4,793
Deferred revenue, net of current portion	54,297	39,825
Roche [Member]
Deferred revenue
Total deferred revenue	39,379	35,709
Other collaborative agreements
Deferred revenue
Total deferred revenue	15,999	8,209
License fees and event-based payments
Deferred revenue
Total deferred revenue	55,378	43,918
Research and Development Services
Deferred revenue
Total deferred revenue	0	700
Product [Member]
Deferred revenue
Total deferred revenue	$ 5,487	$ 0

Long-Term Debt, Net Long-Term D

Long-Term Debt, Net Long-Term Debt Textuals (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount		$ 2,806
Royalty-backed Loan
Debt Instrument [Line Items]
Issuance date		Jan. 26, 2016
Total loan balance		$ 150,000
Debt Instrument, Description of Variable Rate Basis		8.75% plus the three-month LIBOR rate
Debt, Interest Rate		10.25%	9.71%
Debt Instrument, Maturity Date, Description		final maturity date of the Royalty-backed Loan will be the earlier of (i) the date when principal and interest is paid in full, (ii) the termination of Halozyme Royalty’s right to receive royalties under the Collaboration Agreements, and (iii) December 31, 2050
Prepayment fee, percent		105.00%
Debt instrument, covenant in compliance		in compliance
Interest Costs Capitalized		$ 0	$ 13,200
Accrued Interest		700	700
Lender Fee		1,500
Debt Issuance Cost		400
Interest Expense, debt		16,400	14,500
Outstanding loan balance		146,500
Debt Instrument, Unamortized Discount		$ 800
Maturity date		Dec. 31, 2050
Royalty-backed Loan | 2016 [Member]
Debt Instrument [Line Items]
Royalty payments to be applied to debt instrument		0.00%
Royalty-backed Loan | 2017 [Member]
Debt Instrument [Line Items]
Royalty payments to be applied to debt instrument		50.00%
Royalty-backed Loan | 2018 and thereafter [Member]
Debt Instrument [Line Items]
Royalty payments to be applied to debt instrument		100.00%
Royalty-backed Loan | 2017 Quarterly Maximum Payment [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment		$ 13,750
Royalty-backed Loan | 2018 Quarterly Maximum Payment [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment		18,750
Royalty-backed Loan | 2019 Quarterly Maximum Payment [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment		21,250
Royalty-backed Loan | 2020 Quarterly Maximum Payment [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment		$ 22,500
Royalty-backed Loan | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.70%
Royalty-backed Loan | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Secured Debt
Debt Instrument [Line Items]
Total loan balance				$ 50,000
Interest rate, stated percentage				7.55%
Term loan, increase	$ 20,000
Maturity date				Jan. 1, 2018
Final payment as percent of original principal				8.50%
Final payment			4,250	$ 4,250
Senior Loans [Member]
Debt Instrument [Line Items]
Issuance date		Jun. 7, 2016
Total loan balance		$ 70,000
Secured debt original draw		$ 55,000
Interest rate, stated percentage		8.25%
Debt instrument, covenant in compliance		in compliance
Interest Expense, debt		$ 5,500	20,000	$ 5,200
Outstanding loan balance		55,900
Debt Instrument, Unamortized Discount		$ 400
Maturity date		Jan. 1, 2021
Final payment as percent of original principal		5.50%
Debt Instrument, Unused Borrowing Capacity, Amount		$ 15,000
Debt Instrument, interest only period		interest only payments for the first 18 months
Accrued interest, noncurrent		$ 400	$ 1,100
Accretion of debt balloon payment		$ 1,300
Senior Loans [Member] | Minimum [Member]
Debt Instrument [Line Items]
Prepayment fee, percent		1.00%
Senior Loans [Member] | Maximum [Member]
Debt Instrument [Line Items]
Prepayment fee, percent		2.00%

Long-Term Debt, Net Debt Table

Long-Term Debt, Net Debt Table (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,018	$ 94,125
2,019	105,758
2,020	27,311
2,021	4,755
2,022	0
Total minimum payments	231,949
Less amount representing interest	(26,792)
Gross balance of long-term debt	205,157
Less unamortized debt discount	(2,806)
Present value of long-term debt	202,351
Less current portion of long-term debt	(77,211)	$ (17,393)
Long-term debt, less current portion and unamortized debt discount	$ 125,140

Share-based Compensation Textua

Share-based Compensation Textuals (Details)	12 Months Ended
	Dec. 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	6,552,249
Options, Exercise Price, Percent of Share Price	100.00%
Options, Outstanding, Initial Contractual Term	10 years
Cliff Vesting, First Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights, Percentage	25.00%
Monthly Vesting, after One Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights, Percentage	2.08%
RSUs | Percentage Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights, Percentage	25.00%
Outstanding awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Subject To Outstanding Awards	13,023,641
RSAs | Percentage Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights, Percentage	25.00%
Amended and Restated 2011 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Authorized	44,200,000

Share-based Compensation Expens

Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 30,670	$ 25,585	$ 20,838
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	19,583	16,544	11,145
RSU, RSA, and PRSU awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	11,087	9,041	9,693
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	13,080	11,470	9,795
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 17,590	$ 14,115	$ 11,043

Share-based Compensation Unreco

Share-based Compensation Unrecognized Expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 36,914
Compensation Cost Not yet Recognized, Period for Recognition	2 years 5 months
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 4,610
Compensation Cost Not yet Recognized, Period for Recognition	1 year 7 months
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 15,965
Compensation Cost Not yet Recognized, Period for Recognition	2 years 7 months

Share-based Compensation Option

Share-based Compensation Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding, Number, period start	11,091,196	7,993,192	6,353,892
Options, Outstanding, Weighted Average Exercise Price, period start	$ 11.70	$ 13.03	$ 9.18
Options, Grants in Period, Gross	2,717,614	4,466,306	3,973,604
Options, Grants in Period, Weighted Average Exercise Price	$ 12.60	$ 9.03	$ 16.26
Options, Exercises in Period	(1,514,826)	(413,248)	(1,926,368)
Options, Exercises in Period, Weighted Average Exercise Price	$ 9.24	$ 6.88	$ 7.49
Options, Forfeitures and Expirations in Period	(1,185,518)	(955,054)	(407,936)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 11.89	$ 12.42	$ 10.64
Options, Outstanding, Number, period end	11,108,466	11,091,196	7,993,192
Options, Outstanding, Weighted Average Exercise Price, period end	$ 12.24	$ 11.70	$ 13.03
Options, Outstanding, Weighted Average Remaining Contractual Term	7 years
Options, Outstanding, Intrinsic Value	$ 90.8
Options, Vested and Expected to Vest, Outstanding, Number	11,108,466
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 12.24
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	7 years
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 90.8
Options, Vested and Expected to Vest, Exercisable, Number	5,493,802
Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price	$ 12.31
Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	6 years 1 month
Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 44.7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.86	$ 5.36	$ 9.60
Options, Exercises in Period, Intrinsic Value	$ 10	$ 1.4	$ 16.2
Proceeds from Stock Options Exercised	$ 14	$ 2.8	$ 14.4

Share-based Compensation Valuat

Share-based Compensation Valuation (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Share-based Compensation Arrangements Valuation Inputs [Line Items]
Fair Value Assumptions, Weighted Average Expected Term	5 years 7 months	5 years 5 months	5 years 7 months
Fair Value Assumptions, Expected Dividend Rate	0.00%	0.00%	0.00%
Fair Value Assumptions, Risk Free Interest Rate, Minimum	1.73%	1.00%	1.34%
Fair Value Assumptions, Risk Free Interest Rate, Maximum	2.13%	1.90%	1.92%
Minimum [Member]
Schedule of Share-based Compensation Arrangements Valuation Inputs [Line Items]
Fair Value Assumptions, Weighted Average Volatility Rate	69.80%	67.50%	66.20%
Maximum [Member]
Schedule of Share-based Compensation Arrangements Valuation Inputs [Line Items]
Fair Value Assumptions, Weighted Average Volatility Rate	71.70%	71.90%	67.40%

Share-based Compensation Restri

Share-based Compensation Restricted Stock Awards (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Restricted stock award holder exercise price	$ 0
RSAs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, Number, period start	1,303,103	811,480	1,158,451
Nonvested, Weighted Average Grant Date Fair Value, period start	$ 10.09	$ 13.13	$ 10.26
Grants in Period	98,945	968,652	515,695
Grants in Period, Weighted Average Grant Date Fair Value	$ 14.15	$ 8.41	$ 15
Vested in Period	(514,613)	(296,831)	(721,990)
Vested in Period, Weighted Average Grant Date Fair Value	$ 10.23	$ 12.76	$ 10.11
Forfeited in Period	(108,485)	(180,198)	(140,676)
Forfeitures, Weighted Average Grant Date Fair Value	$ 9.62	$ 10.33	$ 11.84
Nonvested, Number, period end	778,950	1,303,103	811,480
Nonvested, Weighted Average Grant Date Fair Value, period end	$ 10.59	$ 10.09	$ 13.13
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in Period, Fair Value	$ 5.3	$ 3.8	$ 7.3
Aggregate Intrinsic Value, Vested	$ 6.6	$ 2.5	$ 13.9

Share-based Compensation Rest64

Share-based Compensation Restricted Stock Units (Details) - RSUs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, Number, period start	1,166,569	666,214	462,322
Nonvested, Weighted Average Grant Date Fair Value, period start	$ 10.16	$ 13.49	$ 11.12
Grants in Period	1,378,273	796,582	422,492
Grants in Period, Weighted Average Grant Date Fair Value	$ 12.13	$ 8.17	$ 14.75
Vested in Period	(378,406)	(218,279)	(134,088)
Vested in Period, Weighted Average Grant Date Fair Value	$ 10.48	$ 12.74	$ 10.93
Forfeited in Period	(251,261)	(77,948)	(84,512)
Forfeitures, Weighted Average Grant Date Fair Value	$ 11.11	$ 10.99	$ 10.86
Nonvested, Number, period end	1,915,175	1,166,569	666,214
Nonvested, Weighted Average Grant Date Fair Value, period end	$ 11.39	$ 10.16	$ 13.49
Outstanding, Weighted Average Remaining Contractual Terms	1 year 5 months
Aggregate Intrinsic Value, Nonvested	$ 38.8
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in Period, Fair Value	4	$ 2.8	$ 1.5
Aggregate Intrinsic Value, Vested	$ 4.7	$ 2.1	$ 1.8

Share-based Compensation Perfor

Share-based Compensation Performance Stock Units (Details) - Performance Shares [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, Number, period start	200,255	309,707	431,238
Nonvested, Weighted Average Grant Date Fair Value, period start	$ 9.49	$ 9.48	$ 8.91
Grants in Period	0	0	118,209
Grants in Period, Weighted Average Grant Date Fair Value	$ 0	$ 0	$ 11.19
Vested in Period	0	(30,037)	(83,380)
Vested in Period, Weighted Average Grant Date Fair Value	$ 0	$ 9.49	$ 9.48
Forfeited in Period	(200,255)	(79,415)	(156,360)
Forfeitures, Weighted Average Grant Date Fair Value	$ 9.49	$ 9.44	$ 9.21
Nonvested, Number, period end	0	200,255	309,707
Nonvested, Weighted Average Grant Date Fair Value, period end	$ 0	$ 9.49	$ 9.48
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in Period, Fair Value	$ 0	$ 0.3	$ 0.8

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) Public Offering (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Shares, New Issues	11.5
Stock Issued During Period Shares New Issues To Underwriter	1.5
Sale of Stock, Price Per Share	$ 12.50
Proceeds from issuance of common stock, net	$ 134,874	$ 0	$ 0

Stockholders' Equity (Deficit67

Stockholders' Equity (Deficit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' equity (deficit) (textual)
Number of shares of common stock issued as a result of stock option exercises	1,514,826	413,248	1,926,368
Net proceeds from stock options exercised	$ 14	$ 2.8	$ 14.4
Stock options
Stockholders' equity (deficit) (textual)
Number of shares of common stock issued as a result of stock option exercises	1,514,826	413,248	1,926,368
Net proceeds from stock options exercised	$ 14	$ 2.8	$ 14.4
RSUs
Stockholders' equity (deficit) (textual)
Shares, Restricted Stock Award	281,398	134,944	82,069
Number of RSUs surrendered to pay for minimum withholding taxes	97,008	83,335	52,019
Payments for tax withholding for restricted stock units vested, net	$ 1.9	$ 0.8	$ 0.7
Restricted stock awards
Stockholders' equity (deficit) (textual)
Shares, Restricted Stock Award	(9,540)	780,066	375,019

Commitments and Contingencies O

Commitments and Contingencies Operating Lease textual (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)ft²	Dec. 31, 2016USD ($)
Office and Research Facility [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Area Leased | ft²	76,000
Operating Leases, Base Rent, Periodic Increase, Percent	3.00%
Deferred Rent Credit | $	$ 0.3	$ 0.4
Number of buildings	4
Lease Expiration Date	Jan. 31, 2023
Satellite office [Member]
Lessee, Lease, Description [Line Items]
Operating Leases, Area Leased | ft²	10,000
Operating Leases, Base Rent, Periodic Increase, Percent	3.00%
Deferred Rent Credit | $	$ 0.3	$ 0.4
Lease Expiration Date	Jan. 31, 2021

Commitments and Contingencies69

Commitments and Contingencies Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense, Net	$ 2,300	$ 2,200	$ 1,900
2,018	2,415
2,019	2,785
2,020	2,824
2,021	2,470
2,022	2,506
2,023	$ 13,000

Commitments and Contingencies70

Commitments and Contingencies Other Commitments (Details) $ in Millions	Dec. 31, 2017USD ($)
Avid Commercial Supply Agreement [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation	$ 7.2
Patheon [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation	$ 0.3

Commitments and Contingencies71

Commitments and Contingencies Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Period for Termination	90 days
Contingent milestone payment	$ 8

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
2017 Federal tax rate	35.00%
2018 Federal tax rate	21.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 17,132	$ 0	$ 0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 17,100

Income Taxes Net Income (Loss)

Income Taxes Net Income (Loss) By Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States	$ 160,938	$ 6,384	$ 11,724
Foreign	(99,328)	(108,245)	(43,955)
Net Income (Loss) Before Income Taxes	$ 61,610	$ (101,861)	$ (32,231)

Income Taxes Components Deferre

Income Taxes Components Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	$ 32,630	$ 103,296
Deferred Tax Assets, Deferred Income	8,815	15,354
Deferred Tax Assets, Tax Credit Carryforwards, Research	75,224	73,701
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	7,423	8,844
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	5,532	1,494
Deferred Tax Assets, Other	2,270	1,021
Deferred Tax Assets, Gross	131,894	203,710
Deferred Tax Assets, Valuation Allowance	(126,189)	(203,370)
Deferred Tax Assets, Net of Valuation Allowance	5,705	340
Deferred Tax Liabilities, Property, Plant and Equipment	(173)	(340)
Deferred Tax Liabilities, Net, Noncurrent	(173)	(340)
Deferred Tax Assets, Net	$ 5,532	$ 0

Income Taxes Income Tax Expense

Income Taxes Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ 4,051	$ 1,145	$ 0
Current State Tax Expense	120	17	0
Deferred Federal Income Tax Benefit	(5,532)	0	0
Deferred State Income Tax Expense	0	0	0
Income tax (benefit) expense	$ (1,361)	$ 1,162	$ 0

Income Taxes Schedule of Income

Income Taxes Schedule of Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	34.00%	34.00%	34.00%
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 20,947	$ (34,633)	$ (10,959)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	930	(653)	5,524
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	(77,181)	11,252	4,045
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	17,132	0	0
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	33,674	36,803	14,945
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount	525	3,735	(4,990)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount	5,779	698	6,457
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	4,162	(1,084)	(3,861)
Effective Income Tax Rate Reconciliation, Deduction, Amount	(7,329)	(14,956)	(11,161)
Income Tax Expense (Benefit), Continuing Operations, Discontinued Operations	$ (1,361)	$ 1,162	$ 0

Income Taxes Unrecognized Tax B

Income Taxes Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, beginning of period	$ 12,799	$ 4,898	$ 0
Increase Resulting from Prior Period Tax Positions	0	5,615	0
Decrease Resulting from Prior Period Tax Positions	(2,518)	(4,898)	0
Increase Resulting from Current Period Tax Positions	4,147	7,184	4,898
Unrecognized Tax Benefits, end of period	$ 14,428	$ 12,799	$ 4,898

Income Taxes Operating Loss Car

Income Taxes Operating Loss Carryforward Expiration (Details) $ in Thousands	Dec. 31, 2017USD ($)
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 88,516
Internal Revenue Service (IRS) [Member] | 2018 expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	0
Internal Revenue Service (IRS) [Member] | 2021 and beyond expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	88,516
Internal Revenue Service (IRS) [Member] | 2028 and beyond expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	0
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	243,080
State and Local Jurisdiction [Member] | 2018 expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	0
State and Local Jurisdiction [Member] | 2021 and beyond expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	0
State and Local Jurisdiction [Member] | 2028 and beyond expiration [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 243,080

Income Taxes Tax textuals (Deta

Income Taxes Tax textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 126,189,000	$ 203,370,000
Unrecognized Tax Benefits	14,428,000	12,799,000	$ 4,898,000	$ 0
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0
Unrecognized Tax Benefits that Would Impact Effective Tax Rate, no valuation allowance	14,400,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0	0	$ 0
Undistributed Earnings of Foreign Subsidiaries	0	$ 0
Deferred Foreign Tax Benefit	0
Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	88,516,000
Internal Revenue Service (IRS) [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 19,100,000
Tax Credit Carryforward, Expiration Date	Dec. 31, 2024
Internal Revenue Service (IRS) [Member] | General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 57,300,000
Tax Credit Carryforward, Expiration Date	Dec. 31, 2035
State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	$ 243,080,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	11,700,000
Other state tax [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards	$ 13,900,000

Employee Savings Plan (Details)

Employee Savings Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Employer Discretionary Contribution Amount	$ 1.2	$ 1	$ 0.7

Summary of Unaudited Quarterl81

Summary of Unaudited Quarterly Financial Information Quarterly Financial Information Table (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 189,564	[1]	$ 63,731	[2]	$ 33,750	$ 29,568	$ 39,003	$ 31,853	$ 33,336	$ 42,499	$ 316,613	$ 146,691	$ 135,057
Gross Profit	5,105		5,257		4,992	3,890	5,420	4,197	5,391	5,178
Operating Expenses	63,635		55,654		59,228	57,094	61,578	54,596	55,059	58,668
Net income (loss)	$ 123,882		$ 2,749		$ (30,763)	$ (32,897)	$ (27,386)	$ (28,946)	$ (26,875)	$ (19,816)	$ 62,971	$ (103,023)	$ (32,231)
Earnings Per Share, Basic	$ 0.87		$ 0.02		$ (0.23)	$ (0.26)					$ 0.46	$ (0.81)	$ (0.25)
Earnings Per Share, Diluted	$ 0.85		$ 0.02		$ (0.23)	$ (0.26)					$ 0.45	$ (0.81)	$ (0.25)
Weighted Average Number of Shares Outstanding, Basic	141,718		141,190		134,013	128,615					136,419	127,964	126,704
Weighted Average Number of Shares Outstanding, Diluted	145,633		143,236		134,013	128,615					139,068	127,964	126,704
Earnings Per Share, Basic and Diluted							$ (0.21)	$ (0.23)	$ (0.21)	$ (0.16)
Weighted Average Number of Shares Outstanding, Basic and Diluted							128,185	128,154	127,958	127,615
[1]	Revenues for the quarter ended December 31, 2017 included $101.4 million, $40.0 million and $15.0 million in revenue under collaborative arrangements from BMS, Alexion and Janssen, respectively.
[2]	Revenues for the quarter ended September 30, 2017 included $30.0 million in revenue under collaborative arrangements from the 2017 Roche Collaboration.

Summary of Unaudited Quarterl82

Summary of Unaudited Quarterly Financial Information Textuals - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017
BMS [Member]
Disaggregation of Revenue [Line Items]
Proceeds from Collaborator	$ 101.4
Alexion [Member]
Disaggregation of Revenue [Line Items]
Proceeds from Collaborator	40
Janssen [Member]
Disaggregation of Revenue [Line Items]
Proceeds from Collaborator	$ 15
Roche [Member]
Disaggregation of Revenue [Line Items]
Proceeds from Collaborator		$ 30

Schedule II Valuation and Qua83

Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable allowance, beginning balance	[1]	$ 559	$ 967	$ 611
Valuation Allowances and Reserves, Additions for Charges to Cost and Expense	[1]	4,645	4,795	4,150
Valuation Allowances and Reserves, Deductions	[1]	(4,645)	(5,203)	(3,794)
Accounts receivable allowance, ending balance	[1]	$ 559	$ 559	$ 967
[1]	Allowances are for chargebacks, prompt payment discounts and distribution fees related to Hylenex recombinant product sales.