Income Tax Expense (Income Tax Benefit Computation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax benefit at federal statutory rate	$ (52,418)	$ (20,315)	$ (11,043)
State income tax expense (benefit), net of federal benefit	(2,323)	(937)	(1,097)
Meals and entertainment	445	328	279
Research and development credits	(2,041)	(1,756)	(4,897)
Stock-based compensation	2,604	1,633	1,161
Derivative gain/loss	14,903	0	0
Contingent consideration	(850)	34	(2,696)
Foreign tax rate differential	1,394	1,013	1,418
Net change in valuation allowance	35,678	10,052	8,930
Return to provision true-up	1,981	583	593
Unrecognized tax benefits	971	928	6,444
Other, net	154	(900)	846
Income tax expense (benefit)	$ 498	$ (9,337)	$ (62)