Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Interest and penalties accrued	$ 0
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at beginning of year	11,500	$ 8,619	$ 7,362
Additions based on tax positions related to the current year	6,017	2,889	1,426
Additions (reductions) for tax positions of prior years	(3)	(8)	(169)
Balance at end of year	17,514	11,500	8,619
Research and development tax credit carryforward
Income Taxes [Line Items]
Unrecognized tax benefits increase	$ 6,000	$ 2,900	$ 1,300