Debt Agreements - Horizon and Molteni warrants (Details)	12 Months Ended
	Dec. 31, 2019 $ / shares
Horizon Warrants
Assumption
Weighted-average fair value of warrants	$ 4.86
Horizon Warrants \| Measurement Input, Price Volatility [Member]
Assumption
Fair Value Assumptions Rate	86.00%
Horizon Warrants \| Expected Term (in years)
Assumption
Fair Value Assumptions Term	7 years
Horizon Warrants \| Risk-free Interest Rate
Assumption
Fair Value Assumptions Rate	2.80%
Horizon Warrants \| Dividend Rate
Assumption
Fair Value Assumptions Rate	0.00%
Molteni Warrants
Assumption
Weighted-average fair value of warrants	$ 4.86
Molteni Warrants \| Measurement Input, Price Volatility [Member]
Assumption
Fair Value Assumptions Rate	86.00%
Molteni Warrants \| Expected Term (in years)
Assumption
Fair Value Assumptions Term	7 years
Molteni Warrants \| Risk-free Interest Rate
Assumption
Fair Value Assumptions Rate	2.80%
Molteni Warrants \| Dividend Rate
Assumption
Fair Value Assumptions Rate	0.00%