Income Taxes - The Components of Net Deferred Income Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Net deferred income tax assets:
Accrued expenses and reserves	$ 13,252	$ 14,001
Stock-based compensation	5,066	5,528
Software	912	602
Goodwill	(8,336)	(7,590)
Net operating loss carryforwards	36,123	38,726
Property and equipment	(8,672)	(7,244)
Convertible debt securities	(16,094)	(16,853)
Deferred revenue	3,556	4,268
Facility abandonments	2,273	2,374
Contingent payments	848	849
Other	3,630	2,294
Total deferred income tax assets	31,968	34,876
Less: valuation allowance	(17,750)	(17,414)
Net deferred income tax assets	14,218	17,462
Net deferred income tax liabilities:
Other	(26)	(182)
Total deferred income tax liabilities	(26)	(182)
Less: valuation allowance	(73)
Net deferred income tax liabilities	(99)	(182)
Client contracts
Net deferred income tax assets:
Client contracts and related intangibles	$ (590)	$ (2,079)