Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net loss	$ (314,061)	$ (237,984)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development	7,000	9,940
Depreciation and amortization expense	7,092	2,254
Stock-based compensation expense	66,925	34,064
Non-cash interest expense	8,588	7,692
Changes in operating assets and liabilities:
Accounts receivable	(21,484)	(15,550)
Inventories	(35,827)	(11,057)
Other assets	(12,415)	(4,551)
Accounts payable	692	(4,766)
Accrued expenses	49,375	15,628
Deferred revenues	(70)	562
Other liabilities	1,000	(728)
Net cash used in operating activities	(243,185)	(204,496)
Investing Activities
Acquisition of product candidates, technology licenses and milestone payments	(42,000)	(9,000)
Purchase of property and equipment	(4,926)	(1,820)
Change in restricted cash	(840)	(120)
Net cash used in investing activities, Total	(47,766)	(10,940)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from sales of common stock, net of issuance costs		613,913
Payments of Stock Issuance Costs	8
Proceeds from exercise of stock options and Employee Stock Purchase Plan	25,849	18,692
Net cash provided by financing activities	25,841	632,605
Effect of exchange rate changes on cash and cash equivalents	498
Increase (decrease) in cash and cash equivalents	(264,612)	417,169
Cash and cash equivalents at beginning of period	785,877	230,146
Cash and cash equivalents at end of period	521,265	647,315
Non-cash investing and financing activities
Stock option exercise proceeds receivable as of period end	71
Leasehold improvement assets funded by lessor	585
Purchase of property and equipment - cash not paid as of period end	328	115
Acquired in-process research and development - milestone not paid as of period end		940
Supplemental cash flow information
Cash paid for interest	6,038	$ 6,038
Income Taxes Paid	$ 468