Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities
Net loss	$ (90,767)	$ (48,506)
Adjustments to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development	4,000
Depreciation and amortization expense	733	99
Stock-based compensation expense	9,258	3,920
Non-cash interest expense	2,472	2,200
Changes in operating assets and liabilities:
Accounts receivable	(377)
Inventories	(4,886)
Other assets	(282)	(352)
Accounts payable	4,293	(464)
Accrued expenses	3,725	1,277
Deferred revenues	2,737
Other liabilities	1,478	1,526
Net cash used in operating activities	(67,616)	(40,300)
Investing activities
Acquisition of product candidate and technology licenses and milestone payments	(4,000)
Purchase of property and equipment	(380)	(172)
Net cash used in investing activities	(4,380)	(172)
Financing activities
Proceeds from sale of common stock, net of issuance costs	154,972	179,950
Proceeds from exercise of stock options	1,338	2,807
Net cash provided by financing activities	156,310	182,757
Increase in cash and cash equivalents	84,314	142,285
Cash and cash equivalents at beginning of period	230,146	256,861
Cash and cash equivalents at end of period	314,460	399,146
Non-cash investing and financing activities
Common stock issuance costs - cash not paid as of period end		$ 204
Stock option exercise proceeds receivable as of period end	$ 82