Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Activities:
Net loss	$ (16,494)	$ (5,319)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	245	147
Amortization of premium on marketable securities	72	241
Stock-based compensation	3,194	2,953
Change in fair value of contingent consideration liability		(1,800)
Intangible impairment		1,870
Benefit from income taxes		(748)
Net changes in operating assets and liabilities:
Interest receivable	(95)	25
Accounts receivable	(46)	3,730
Prepaid expenses and other assets	172	101
Accounts payable and accrued liabilities	(5,158)	(2,477)
Accrued compensation and employee benefits	(1,026)	(1,150)
Deferred revenues	(1,224)	34
Net cash used in operating activities	(20,360)	(2,393)
Investing Activities:
Purchases of marketable securities	(84,816)	(39,423)
Maturities of marketable securities	68,770	58,955
Purchases of property and equipment	(252)	(1,084)
Net cash provided by / (used in) investing activities	(16,298)	18,448
Financing Activities:
Taxes paid related to net share settlement of equity awards	(2)	(7)
Proceeds from issuance of common stock	187	3,178
Net cash provided by financing activities	185	3,171
Net increase / (decrease) in cash and cash equivalents	(36,473)	19,226
Cash and cash equivalents, beginning of period	69,482	6,030
Cash and cash equivalents, end of period	33,009	25,256
Supplemental disclosure of noncash investing activities:
Property and equipment included in accrued liabilities	$ 253	$ 579