Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
U.S. statutory income tax rate	21.00%	21.00%	21.00%
State tax, net of U.S. federal tax benefit	3.80%	3.80%	5.70%
Non-U.S. income taxes	0.40%	0.00%	0.10%
Nondeductible operating expenses	0.20%	(0.40%)	3.10%
Research and development credit	(1.00%)	0.50%	(3.10%)
Change in deferred tax measurement rate	(5.50%)	(0.10%)	0.10%
Change in uncertain tax positions	0.20%	0.10%	0.80%
Excess tax benefits from stock plans	(1.50%)	(0.20%)	(0.70%)
Valuation allowance	34.30%	(1.50%)	1.80%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent	0.00%	(13.60%)	0.00%
Effective Income Tax Rate Reconciliation, Capital Income (Loss), Percent	(34.80%)	0.00%	0.00%
Other	(0.30%)	(0.20%)	(0.70%)
Effective income tax rate for continuing operations	16.80%	9.40%	28.10%
Valuation allowance	$ 26,985	$ 2,743
Loss and Other Credit Carryforward | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 200