Income Taxes - Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax assets:
Net operating loss carryforward	$ 1,834	$ 2,341
Deferred revenue	21,055	15,348
Deferred compensation	1,175	971
Lease liability	5,730	2,460
Inventory reserve	511	1,258
Stock-based compensation	18,890	10,769
Amortization	2,436	1,133
Research and development tax credit carryforward	6,654	4,957
Reserves, accruals, and other	7,274	3,394
Total deferred income tax assets	65,559	42,631
Deferred income tax liabilities:
Contract asset	(1,150)	(883)
Right of use asset	(5,237)	(2,228)
Depreciation	(5,363)	(3,715)
Amortization		(62)
Investment in unconsolidated affiliate	(321)
Prepaid expenses	(874)	(600)
Other	(185)	(637)
Total deferred income tax liabilities	(13,130)	(8,125)
Net deferred income tax assets before valuation allowance	52,429	34,506
Valuation allowance	(7,308)	(7,172)
Net deferred income tax assets	$ 45,121	$ 27,334