Income Taxes - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Increase (decrease) in IRC 162(m) limitation	$ 500,000
Decrease in excess tax benefit, shared-based compensation and additional expenses	3,900,000
Discrete tax benefits related to excess tax benefits from stock-based compensation	500,000	$ 4,400,000
Deferred tax assets, valuation allowance	0		$ 0
Unrecognized tax benefits	9,833,000	8,078,000	$ 8,398,000	$ 6,965,000
Unrecognized tax benefits, income tax penalties and interest accrued	800,000	$ 400,000
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	31,900,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	57,900,000
Operating loss carryforward, subject to expiration	31,700,000
Operating loss carryforward, not subject to expiration	26,200,000
State | Latest tax year
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	16,300,000
State | Tax year 2023-2027
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 1,100,000