Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Tax expense (benefit) at U.S. federal income tax rate	$ 5,364	$ (7,270)	$ 15,957
State income taxes, net of federal income tax effect	449	500	1,410
Effect of non-US operations	(501)	(254)	(1,621)
Nontaxable contingent liability fair value changes and goodwill impairment	3,578	13,083	(14,334)
Research and development credit	(297)	(422)	(376)
Change in valuation allowances	2,206	5,173	850
Prior year provision to return adjustment	(137)	372	(172)
Write-off of deferred taxes and tax receivables	0	858	0
Change in valuation allowances	293	252	141
Prior year provision to return adjustment	$ 10,955	$ 12,292	$ 1,855