Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Reserves and accruals	$ 1,839	$ 1,892
Stock-based compensation	1,116	686
Net operating losses	30,750	25,558
Other	1,753	1,780
Amortization	642	344
Deferred tax assets	36,100	30,260
Depreciation	(285)	(212)
State tax	(2,034)	(1,706)
Deferred tax liabilities	(2,319)	(1,918)
Valuation allowance	(33,781)	(28,342)
Net deferred tax (liabilities) assets	$ 0	$ 0