Property and Equipment, Net - Component of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 159,443	$ 83,718
Less: accumulated depreciation	(51,579)	(38,965)
Total property and equipment, net	107,864	44,753
Land
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,525	0
Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Total property and equipment	$ 60,878	53,246
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,038	694
Computers
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Total property and equipment	$ 3,659	2,833
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	2,521	1,960
Leasehold improvement
Property, Plant and Equipment [Line Items]
Total property and equipment	1,425	1,126
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 87,397	$ 23,859
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	2 years
Minimum | Lab equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Minimum | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Maximum | Lab equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Maximum | Computers
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Maximum | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years