Common Stock Incentive Plan - Summary (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Common Stock Incentive Plan
Severance charge	$ 3,500,000
2012 Plan
Common Stock Incentive Plan
Plan term from the date of adoption	10 years
General and administrative expense
Common Stock Incentive Plan
Share-based compensation costs recognized	$ 5,500,000	$ 2,800,000
Accelerated share-based compensation costs	$ 1,800,000
Maximum | 2012 Plan
Common Stock Incentive Plan
Authorized shares	3,985,734
Cash
Common Stock Incentive Plan
Severance charge	$ 1,600,000
Share-based compensation
Common Stock Incentive Plan
Severance charge	1,800,000
Professional fees
Common Stock Incentive Plan
Severance charge	$ 58,000