Debt - Narrative (Details) - USD ($)	3 Months Ended	6 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2016	Sep. 02, 2016
Debt Instrument [Line Items]
Fair value of warrant	$ 7,059,262		$ 7,059,262	$ 7,059,262				$ 6,727,409
London Interbank Offered Rate (LIBOR) | Loan Agreement
Debt Instrument [Line Items]
Margin for term loan			11.50%
Effective interest rate (as a percent)			18.50%
Warrants
Debt Instrument [Line Items]
Fair value of warrant	7,100,000		$ 7,100,000	7,100,000					$ 5,800,000
Secured Debt | Loan Agreement
Debt Instrument [Line Items]
Line of credit facility	80,000,000		80,000,000	80,000,000					80,000,000
Interest expense, debt	3,700,000		7,300,000
Interest paid on term loan	2,500,000		5,100,000
Interest expense accreted to balance	1,100,000		$ 2,200,000
Minimum cash requirement				15,000,000
Potential increase in interest rate			2.00%
Costs incurred									$ 8,200,000
Fees and expenses	4,000,000		$ 4,000,000	4,000,000
Remaining borrowing capacity	68,800,000		$ 68,800,000	68,800,000
Secured Debt | US Treasury Rate | Loan Agreement
Debt Instrument [Line Items]
Margin for term loan			0.50%
Secured Debt | Repayment of Interests | Loan Agreement
Debt Instrument [Line Items]
Capacity available for specific purpose other than for trade purchases	25,000,000		$ 25,000,000	25,000,000
Secured Debt | Payments Related to Litigation | Loan Agreement
Debt Instrument [Line Items]
Capacity available for specific purpose other than for trade purchases	$ 50,000,000		$ 50,000,000	$ 50,000,000
Secured Debt | Forecast | Loan Agreement
Debt Instrument [Line Items]
Additional borrowing capacity							$ 5,000,000
Minimum cash requirement		$ 10,000,000			$ 20,000,000	$ 5,000,000