Income Tax Expense (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred:
Net operating loss carryforwards	$ 66,280	$ 56,331
Accrued expenses	4,391	4,274
Tax credits	8,438	7,368
Bad debt	81	72
Inventory	2,307	2,121
Capitalized research and development	8,948	6,586
Deferred compensation	3,075	2,587
Other	1,659	0
Deferred tax asset	95,179	79,339
Valuation allowance	(67,172)	(57,883)
Total deferred tax assets	28,007	21,456
Deferred Tax Liabilities, Net [Abstract]
Depreciation and amortization	(1,183)	(2,077)
Convertible debt	(12,056)	(3,595)
Other	0	(85)
Total deferred tax liabilities	(28,886)	(22,335)
Net deferred tax liability	(879)	(879)
Trademarks and trade names
Deferred Tax Liabilities, Net [Abstract]
Intangible assets	(1,002)	(1,043)
Developed Technology and Trademark
Deferred Tax Liabilities, Net [Abstract]
Intangible assets	$ (14,645)	$ (15,535)