Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash Flows from Operating Activities
Net loss	$ (28,827,000)	$ (16,616,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	357,000	93,000
Amortization of intangible assets	137,000	0
Accretion of discounts and amortization of premiums on marketable securities	550,000
Stock-based compensation	3,743,000	580,000
Excess tax benefit from stock-based compensation	(2,161,000)
Gain from remeasurement of fair value of contingent consideration	(317,000)
Loss from remeasurement of fair value of warrants		9,342,000
Changes in operating assets and liabilities:
Accounts receivable	2,979,000	2,622,000
Prepaid expenses and other assets	(6,021,000)	(776,000)
Accounts payable	140,000	1,018,000
Deferred revenue	(3,761,000)	(9,072,000)
Accrued clinical trial and manufacturing expenses	5,092,000	1,353,000
Accrued expenses and other liabilities	4,726,000	2,985,000
Net cash used in operating activities	(23,363,000)	(8,471,000)
Cash Flows from Investing Activities
Purchase of marketable securities	(138,564,000)
Proceeds from maturities of marketable securities	130,509,000
Purchase of property and equipment	(1,365,000)	(314,000)
Net cash used in investing activities	(9,420,000)	(314,000)
Cash Flows from Financing Activities
Deferred offering costs		(297,000)
Proceeds from issuance of convertible preferred stock, net of issuance costs		22,522,000
Excess tax benefit from stock-based compensation	2,161,000
Proceeds from exercise of stock options and warrants	299,000	88,000
Net cash provided by financing activities	2,460,000	22,313,000
Net (decrease) increase in cash and cash equivalents	(30,323,000)	13,528,000
Cash and cash equivalents at beginning of period	150,456,000	119,456,000
Cash and cash equivalents at end of period	120,133,000	132,984,000
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Accrued offering costs		910,000
Purchase of property and equipment in accounts payable and accrued liabilities	$ 1,159,000	$ 214,000