Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities
Net loss	$ (288,784)	$ (150,134)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development	7,000	8,000
Depreciation and amortization expense	4,931	1,479
Stock-based compensation expense	41,909	21,146
Non-cash interest expense	5,672	5,082
Changes in operating assets and liabilities:
Accounts receivable	(16,954)	1,152
Inventories	(6,959)	(7,275)
Other assets	(10,950)	(2,112)
Accounts payable	(5,146)	5,859
Accrued expenses	19,746	6,506
Deferred revenues	(46)	417
Other liabilities	94	(49)
Net cash used in operating activities	(249,487)	(109,929)
Investing Activities
Acquisition of product candidate and technology licenses and milestone payments	(42,000)	(8,000)
Purchase of property and equipment	(4,309)	(590)
Change in restricted cash	(846)
Net cash used in investing activities, Total	(47,155)	(8,590)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from sales of common stock, net of issuance costs		204,969
Payments of Stock Issuance Costs	8
Proceeds from exercise of stock options and Employee Stock Purchase Plan	18,348	3,608
Net cash provided by financing activities	18,340	208,577
Effect of Exchange Rate on Cash and Cash Equivalents	366
Increase (decrease) in cash and cash equivalents	(277,936)	90,058
Cash and cash equivalents at beginning of period	785,877	230,146
Cash and cash equivalents at end of period	507,941	320,204
Non-cash investing and financing activities
Stock option exercise proceeds receivable as of period end	35	2,875
Leasehold improvement assets funded by lessor	585
Purchase of property and equipment - cash not paid as of period end	118	139
Supplemental cash flow information
Cash paid for interest	$ 3,019	$ 3,019