Subsequent events (Details) - Subsequent event	May 11, 2020 USD ($) employee	May 06, 2020 USD ($) $ / shares	Apr. 18, 2020 USD ($)
Restructuring Costs [Abstract]
Restructuring and related activities initiation date	May 11, 2020
Percentage of workforce reduced	25.00%
Number of employees reduced | employee	50
Restructuring and related activities completion date	May 15, 2020
Total restructuring cost	$ 1,200,000
RestructuringCosts	1,100,000
Fifth Amendment To Credit Facility
Subsequent events
Repayments of debt	$ 10,000,000
Deferred Principal		$ 5,000,000
Number of monthly installments		8 months
Conversion price (in dollars per share) | $ / shares		$ 1.50
Minimum share price for deferral of loan payment | $ / shares		$ 1.50
Number of consecutive days where the stock price must exceed $1.50		10 days
Non-refundable exit fee		$ 250,000
Fifth Amendment To Credit Facility | Maximum
Subsequent events
Convertible Debt		10,000,000
U S Small Business Administration Paycheck Protection Program Loan [Member]
Subsequent events
Proceeds from issuance of debt			$ 3,600,000
Repayments of debt		$ 3,600,000