Stockholders' equity (Tables)

12 Months Ended

Dec. 31, 2021

Stockholders' equity

Summary of share-based compensation expense for all stock awards

Stock-based compensation expense for all stock awards consists of the following (in thousands):

	December 31,
	2021		2020		2019
Cost of product revenue	$	471	$	189	$	86
Cost of service and other revenue		403		311		238
Research and development		1,807		1,129		718
Selling, general, and administrative		13,294		8,470		5,346
Total stock-based compensation	$	15,975	$	10,099	$	6,388

Summary of warrant activity

The following table summarizes the Company’s outstanding warrants:

		Weighted
	Issued and	Average
	exercisable	Exercise Price
As of December 31, 2020	10,000	$	21.00
Issued	—		—
Exercised	(10,000)		21.00
Cancelled	—		—
As of December 31, 2021	—	$	—

Summary of stock option activity

		Weighted-average		Remaining contractual	intrinsic value
	Options	exercise price		life (in years)	(in thousands)
Outstanding at December 31, 2020	2,494,045	$	17.73	7.27	$	71,760
Granted	439,209	$	62.06
Exercised	(516,804)	$	15.24
Cancelled	(211,637)	$	36.32
Outstanding at December 31, 2021	2,204,813	$	25.36	6.76	$	44,813
Exercisable at December 31, 2021	1,493,289	$	16.34	5.90	$	39,191
Vested and expected to vest at December 31, 2021	2,204,813	$	25.36	6.76	$	44,813

Summary of restricted stock units activity

		Weighted-average		Weighted-average		Aggregate
		grant date fair		remaining contractual		intrinsic value
	Shares	value per share		life (in years)		(in thousands)
Unvested RSUs as of December 31, 2020	478,581	$	28.08	8.83	$	22,254
Granted	428,235	$	58.20
Vested	(267,189)	$	27.31
Cancelled	(109,756)	$	44.64
Unvested RSUs as of December 31, 2021	529,871		49.32	9.68	$	22,467
Expected to convert at December 31, 2021	529,871	$	49.32		$	22,467