License, Collaboration and Other Significant Agreements - Schedule of Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liabilities, Balance at End of Period		$ 76,029
Other Current Assets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract assets, Additions		10,000	$ 531
Contract assets, Deductions		(10,000)	(531)
Accounts Receivable
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract assets, Balance at Beginning of Period	[1]	1,587	34,186
Contract assets, Additions	[1]	134,268	120,283
Contract assets, Deductions	[1]	(131,651)	(153,938)
Contract assets, Balance at End of Period	[1]	4,204	531
Deferred Revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liabilities, Balance at Beginning of Period		112,689	179,624
Contract liabilities, Additions		131,444	119,442
Contract liabilities, Deductions		(168,104)	(147,543)
Contract liabilities, Balance at End of Period		76,029	151,523
Accounts Payable
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liabilities, Balance at Beginning of Period		13,492
Contract liabilities, Additions			4,427
Contract liabilities, Deductions		$ (13,492)	(1,040)
Contract liabilities, Balance at End of Period			$ 3,387

[1] Excludes accounts receivable from other services related to clinical and regulatory activities performed by the Company on behalf of MTPC that are not included in the performance obligations identified under the MTPC Agreement as of September 30, 2018 and 2019 and December 31, 2017 and 2018.