Stockholders' Equity - Registration Rights Agreement (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Maximum amount of repurchase rights agreement	$ 50
Effectiveness penalty percentage	0.25%
Purchase price allocation percentage	0.75%
5% Convertible Senior Notes due 2021 | Convertible Debt
Debt Instrument [Line Items]
Interest rate on the 90th day following registration statement	0.25%
Interest rate on the 91st day following the registration statement	0.50%
Registration statement liquidation damages limit	0.50%