Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Net operating losses	$ 32,734	$ 27,526
Research credits	3,047	3,020
Property and equipment	488	427
Intangible assets and goodwill	1,496	1,669
Other	3,297	3,015
Total deferred tax assets	41,062	35,657
Valuation allowance	(39,725)	(34,039)	$ (30,235)
Net deferred tax assets	1,337	1,618
Deferred tax liabilities
Intangible assets and goodwill	(291)	(332)
Capitalized internal-use software	(815)	(931)
Other	(231)	(355)
Total deferred tax liabilities	(1,337)	(1,618)
Net deferred tax liabilities	$ 0	$ 0