Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 24,569	$ 21,212
Allowance for doubtful accounts	981	1,582
Inventory valuation reserves	827	2,205
Equity compensation	685	3,161
Goodwill	0	10,788
Accrued compensation	222	80
Foreign tax credit carryforward	3,955	2,365
Other	0	76
Total gross deferred tax assets	31,239	41,469
Valuation allowance	(1,187)	(1,053)
Total deferred tax assets, net	30,052	40,416
Deferred tax liabilities:
Property and equipment	(6,216)	(7,264)
Intangible assets	(10,084)	(13,375)
Goodwill	(365)	0
Convertible debt	(619)	(2,010)
Unearned revenue	(52)	(4,535)
Prepaid insurance and other	(3)	(338)
Total gross deferred tax liabilities	(17,339)	(27,522)
Net deferred tax assets	$ 12,713	$ 12,894