Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 70,430		$ 66,797
Accumulated depreciation	(50,619)		(48,829)
Property and equipment, net	19,811		17,968
Depreciation expense	1,400	$ 1,300
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,829		3,732
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Useful life (years)	3 years
Computer hardware and software | Maximum
Property, Plant and Equipment [Line Items]
Useful life (years)	5 years
Manufacturing and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 46,751		43,432
Manufacturing and lab equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life (years)	2 years
Manufacturing and lab equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life (years)	7 years
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,129		1,053
Office equipment and furniture | Minimum
Property, Plant and Equipment [Line Items]
Useful life (years)	5 years
Office equipment and furniture | Maximum
Property, Plant and Equipment [Line Items]
Useful life (years)	7 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 18,721		$ 18,580
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life (years)	2 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life (years)	12 years