Stock compensation plan (Tables)

3 Months Ended

Mar. 31, 2021

Stock compensation plan

Schedule of weighted-average assumptions used to estimate the fair value

	Three months		Three months
	ended		ended
	March 31,		March 31,
	2021		2020
Weighted-average risk-free interest rate	1.0	%	1.1	%
Expected dividend yield	0	%	0	%
Expected volatility	51.0	%	45.1	%
Expected term	6.1 years		4.9 years

Schedule of Stock-based compensation expense allocated

	Three months ended
	March 31,
	2021		2020
Cost of goods sold	$	16	$	2
Selling, general and administrative		183		231
Research and development		55		79
Total stock-based compensation	$	254	$	312