Significant accounting policies (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Impact on consolidated balance sheet and statement of operations, as a result of adopting ASU 842
Operating Lease, Right-of-Use Asset	$ 12,120
Operating Lease, Liability, Noncurrent	22,458
Restatement adjustment | ASU 2016-02
Impact on consolidated balance sheet and statement of operations, as a result of adopting ASU 842
Operating Lease, Right-of-Use Asset	12,200
Operating Lease, Liability, Noncurrent	$ 22,800