Annual report pursuant to Section 13 and 15(d)

Debt Agreements - Additional information (Details)

Debt Agreements - Additional information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended					12 Months Ended
	Jul. 27, 2017	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2018	Feb. 28, 2018	Jul. 27, 2017	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 21, 2018
Deemed Dividend On Trigger Down Round Provision							$ 0	$ 285
Gain (Loss) on Extinguishment of Debt							$ 226	$ 0
Horizon Technology Finance Corporation
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 1.50
Class of Warrant or Right, Number of Securities Called by Warrants or Rights									366,668
Class Of Warrant Or Right Terms	7 years
Venture Loan
Debt Instrument, Face Amount	$ 7,000					$ 7,000
Debt Instrument Final Payment On Each Loan Tranche percentage						5.00%
Early Repayment of Subordinated Debt					$ 3,000
Long-term Debt					$ 7,000
Venture Loan \| Horizon Technology Finance Corporation
Debt Instrument, Term	46 months
Debt Instrument, Description of Variable Rate Basis						one-month LIBOR (floor of 1.10%) plus 8.40%
Molteni Loan
Class Of Warrant Or Right Terms				7 years
Long-term Debt										$ 4,000
Conversion Price, (in dollars per share)		$ 0.225
Debt Conversion, Converted Instrument, Shares Issued		3,422,777					3,422,777
Gain (Loss) on Extinguishment of Debt							$ 300
Increase in Repayment of Long-term Debt		$ 300
Horizon Loan
Class of Warrant or Right, Exercise Price of Warrants or Rights										$ 7.20
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										6,667
Long-term Debt										$ 2,400
Conversion Price, (in dollars per share)										$ 7.20
Stockholders' Equity Note, Changes in Capital Structure, Subsequent Changes to Number of Common Shares, Amount				$ 10,000
Debt Instrument, Periodic Payment				$ 1,600
Molteni Purchase Agreement
Conversion Price, (in dollars per share)			$ 1.50
Debt Conversion, Converted Instrument, Shares Issued			448,287
Gain (Loss) on Extinguishment of Debt			$ 100
Minimum [Member] \| Venture Loan \| Horizon Technology Finance Corporation
Debt Instrument Additional Face Amount	$ 10,000					$ 10,000
New Horizon Warrants
Class of Warrant or Right, Exercise Price of Warrants or Rights										$ 7.20
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										90,000