Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Valuation allowance	$ 41,922	$ 28,953	$ 24,736
Increase (decrease) in deferred tax asset valuation allowance	13,000	4,200	(2,000)
Write off of net operating losses			3,100
Write off of tax credits			1,200
Unrecognized tax benefits	8,248	$ 989	$ 942	$ 1,070
Federal
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	122,500
Federal | Tax Year 2018
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	50,500
State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	90,300
Research and Development | Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward	2,800
Research and Development | State
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 4,200