Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue:
Total revenue	$ 20,206	$ 18,628
Cost of sales:
Total cost of sales	6,379	6,177
Gross profit	13,827	12,451
Operating expenses:
Research and development	17,573	13,027
General and administrative	11,716	8,967
Sales and marketing	5,811	5,606
Total operating expenses	35,100	27,600
Loss from operations	(21,273)	(15,149)
Other income (expense):
Interest expense	(224)	(354)
Interest income	34	66
Other income, net	57	19
Loss before income taxes	(21,406)	(15,418)
Provision for income taxes	20	17
Net loss and comprehensive loss	(21,426)	(15,435)
Net loss and comprehensive loss	$ (21,426)	$ (15,435)
Net loss attributable to common stockholders per share, diluted (in dollars per share)	$ (0.32)	$ (0.24)
Net loss attributable to common stockholders per share, basic (in dollars per share)	$ (0.32)	$ (0.24)
Weighted-average shares used in calculating net loss per share, basic (in shares)	67,697,488	65,259,398
Weighted-average shares used in calculating net loss per share, diluted (in shares)	67,697,488	65,259,398
Product
Revenue:
Total revenue	$ 9,774	$ 13,533
Cost of sales:
Total cost of sales	2,695	3,703
Service
Revenue:
Total revenue	10,432	5,095
Cost of sales:
Total cost of sales	$ 3,684	$ 2,474