Income taxes - Schedule of Components of Net Deferred Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Compensation	$ 760	$ 895	$ 928
Inventories and receivables	3,472	2,915	3,008
Accrued expenses	1,996	667	424
Stock compensation	3,706	3,627	5,175
Net operating losses	92	236	43
Right of use liability	3,443	4,643	0
Other	558	736	898
Deferred tax assets	14,027	13,719	10,476
Deferred tax liabilities:
Goodwill	3,468	2,857	2,618
Fixed assets	3,294	1,734	2,405
Intangible assets	25,287	24,077	24,591
Right of use asset	3,292	887	0
Other	563	892	1,023
Deferred tax liabilities	35,904	30,447	30,637
Net deferred tax liabilities	$ 21,877	$ 16,728	$ 20,161