Long-term debt - Summary (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Long-term debt
Long term debt and finance lease obligations, including current maturities	$ 44,896	$ 51,774
Less current portion of long term debt	(16,108)	(8,557)
Long-term debt, net of current	28,788	43,217
Debt instrument, unamortized discount
Unamortized discount on debt	2,317
Debt issued to entities affiliated with Deerfield \| Senior Secured Credit Facility
Long-term debt
Long term debt and finance lease obligations, including current maturities	43,433	49,916
Debt instrument, unamortized discount
Unamortized discount on debt	2,317	3,334
Financing and capital leases, maturing through May 2024 \| Senior Secured Credit Facility
Long-term debt
Long term debt and finance lease obligations, including current maturities	$ 1,463	$ 1,858

Amount, after accumulated amortization, of debt discount.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant