Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Accrued expenses and allowances	$ 993	$ 793	$ 733
Deferred revenue	573	671	549
Stock compensation	1,054	582	350
Net operating loss and tax credit carryforwards	24,895	20,871	16,755
Capital expenses	307	0	0
Other	176	196	123
Valuation allowance for noncurrent deferred tax assets	(24,588)	(18,507)	(13,107)
Net deferred tax assets	3,410	4,606	5,403
Deferred tax liabilities:
Capital expenses		(2)	(202)
Prepaid expenses	(31)	(1)	(1)
Intangible assets	(5,718)	(6,481)	(7,217)
Goodwill	(1,029)	(561)	(252)
Tax credit carryforwards	(38)	(379)	(737)
Net deferred tax liabilities	(6,816)	(7,424)	(8,409)
Net deferred taxes	$ (3,406)	$ (2,818)	$ (3,006)