Debt - MidCap Facility Agreement (Details) - Amended credit facility with MidCap - USD ($)			9 Months Ended
	Nov. 06, 2018	Mar. 08, 2018	Sep. 30, 2018
Line of Credit Facility [Line Items]
Unamortized debt discount			$ 1,100,000
Minimum liquidity covenant amount		$ 5,000,000
Latest date of minimum liquidity covenant		2019-03
Subsequent Event
Line of Credit Facility [Line Items]
Latest date of minimum liquidity covenant	2020-03
Maximum
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility		2019-04
Maximum | Subsequent Event
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility	2020-04
Minimum
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility		2018-04
Minimum | Subsequent Event
Line of Credit Facility [Line Items]
Effective date of financial covenants of amended credit facility	2019-04
Line of credit | Maximum
Line of Credit Facility [Line Items]
Debt default, interest rate increase			5.00%
Revolving credit facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 22,500,000
Line of credit			$ 9,500,000
Interest rate			8.10%
Revolving credit facility | LIBOR
Line of Credit Facility [Line Items]
Interest rate description			LIBOR”) plus 6.0%
Basis spread			6.00%
Term Loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 5,000,000