Debt - Squadron Credit Agreement (Details) - USD ($)	Mar. 27, 2019	Nov. 06, 2018	Sep. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Minimum liquidity covenant amount				$ 5,000,000
Squadron Credit Agreement
Line of Credit Facility [Line Items]
Current interest rate		10.50%
Debt instrument, aggregate principal to be paid on installments		$ 10,000,000
Debt instrument, frequency of periodic payment		29 equal monthly installments
Debt instrument payment at maturity		$ 25,000,000
Debt instrument, maturity date		Nov. 30, 2023
Debt carrying amount, net of issuance cost		$ 32,400,000
Debt issuance cost, amortization period		5 years
Squadron Credit Agreement | Subsequent Event
Line of Credit Facility [Line Items]
Debt instrument, frequency of periodic payment	29 equal monthly installments
Debt instrument, maturity date	Nov. 30, 2023
Squadron Credit Agreement | Expanded Credit Facility | Subsequent Event
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 30,000,000
Squadron Credit Agreement | Common Stock
Line of Credit Facility [Line Items]
Number of warrants issued (in shares)		845,000
Exercise price of warrants		$ 3.15
Warrants term		7 years
Squadron Credit Agreement | Common Stock | Subsequent Event
Line of Credit Facility [Line Items]
Number of warrants issued (in shares)	4,800,000
Exercise price of warrants	$ 2.17
Warrants term	7 years
Squadron Credit Agreement | Minimum
Line of Credit Facility [Line Items]
Current interest rate		10.00%
Squadron Credit Agreement | Maximum
Line of Credit Facility [Line Items]
Current interest rate		13.00%
Globus facility agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 30,000,000		$ 30,000,000
Term Loan | Squadron Credit Agreement
Line of Credit Facility [Line Items]
Secured debt agreement		$ 35,000,000		$ 35,000,000
Proceeds from secured term loan		34,100,000
Term Loan | Squadron Credit Agreement | Subsequent Event
Line of Credit Facility [Line Items]
Secured debt agreement	$ 30,000,000
Line of credit | Squadron Credit Agreement
Line of Credit Facility [Line Items]
Minimum liquidity covenant amount		$ 5,000,000
Fixed Charge Coverage Ratio		100.00%
Line of credit | Squadron Credit Agreement | Subsequent Event
Line of Credit Facility [Line Items]
Line of credit	$ 0
Line of credit | Squadron Credit Agreement | Maximum
Line of Credit Facility [Line Items]
Debt default, interest rate increase		5.00%
Line of credit | Squadron Credit Agreement | LIBOR
Line of Credit Facility [Line Items]
Line of credit, expiration period		5 years
Interest rate description		LIBOR plus 8%
Line of credit | Squadron Credit Agreement | LIBOR | Subsequent Event
Line of Credit Facility [Line Items]
Interest rate description	LIBOR plus 8%
Line of credit | Globus facility agreement
Line of Credit Facility [Line Items]
Line of credit		$ 29,200,000
Line of credit, expiration period			5 years