Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net loss	$ (466,555)	$ (314,061)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development		7,000
Depreciation and amortization expense	7,139	7,092
Stock-based compensation expense	79,295	66,925
Non-cash interest expense	10,477	8,588
Gain on sale of business	(17,627)
Changes in operating assets and liabilities:
Accounts receivable	6,063	(21,484)
Inventories	(54,647)	(35,827)
Other assets	3,629	(12,415)
Accounts payable	23,921	692
Accrued expenses	12,178	49,375
Deferred revenues	146	(70)
Other liabilities	2,187	1,000
Net cash used in operating activities	(393,794)	(243,185)
Investing activities
Acquisition of product candidates, technology licenses and milestone payments		(42,000)
Proceeds from sale of business	35,000
Purchase of property and equipment	(3,757)	(4,926)
Net cash provided by (used in) investing activities	31,243	(46,926)
Financing activities
Proceeds from term loan, net of issuance costs	196,000
Proceeds from sale of common stock, net of issuance costs		(8)
Proceeds from exercise of stock options and Employee Stock Purchase Plan	8,734	25,849
Net cash provided by financing activities	204,734	25,841
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(2,409)	498
Decrease in cash, cash equivalents, and restricted cash	(160,226)	(263,772)
Cash, cash equivalents, and restricted cash at beginning of period	645,954	787,866
Cash, cash equivalents, and restricted cash at end of period	485,728	524,094
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
Supplemental disclosure of cash flow information
Cash paid for interest	33,099	6,038
Income taxes paid	$ 921	$ 468