Other accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other accrued expenses
Accrued inventory purchases	$ 527	$ 459
Accrued royalties	1,845	476
Accrued professional services	797	655
Accrued development costs	323	151
Accrued other	1,353	757
Total accrued expenses	$ 4,845	$ 2,498