Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Increase in goodwill	$ 0	$ 12,272,000
Goodwill	12,272,000	12,272,000	$ 0
Goodwill, impairment	0
Impairments on cancelled patent	2,777,000
Impairment of intangible asset	1,959,000	0	0
Net carrying value	39,244,000	53,362,000
Impairment of intangible asset	12,047,000	13,385,000	8,453,000
Canceled Patent
Finite-Lived Intangible Assets [Line Items]
Impairments on cancelled patent	2,777,000
Write-off of accumulated amortization on intangible assets	818,000
Impairment of intangible asset	1,959,000
Net carrying value	0
Operating Expense
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible asset	12,159,000	13,495,000	8,562,000
Cost of Sales
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible asset	$ 112,000	$ 110,000	$ 109,000