Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 37,317	$ 36,305
Less accumulated depreciation	(25,484)	(23,977)
Property and equipment, net	11,833	12,328
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	5,321	5,321
Lab and clean room equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,128	14,894
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,405	15,118
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,463	$ 972