Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Total revenue	$ 24,324	$ 18,208	$ 62,202	$ 42,555
Cost of sales:
Total cost of sales	8,911	5,400	21,610	12,806
Gross profit	15,413	12,808	40,592	29,749
Operating expenses:
Research and development	16,195	10,421	42,757	33,240
General and administrative	12,258	7,229	32,950	15,419
Sales and marketing	6,940	3,341	17,863	9,651
Total operating expenses	35,393	20,991	93,570	58,310
Loss from operations	(19,980)	(8,183)	(52,978)	(28,561)
Other income (expense):
Interest expense	(232)	(361)	(942)	(1,074)
Interest income	33	51	142	249
Other income (expense) , net	(170)	10	(117)	72
Loss before income taxes	(20,349)	(8,483)	(53,895)	(29,314)
Provision for income taxes	54	118	97	142
Net loss and net comprehensive loss	(20,403)	(8,601)	(53,992)	(29,456)
Net loss and net comprehensive loss	$ (20,403)	$ (8,601)	$ (53,992)	$ (29,456)
Net loss attributable to common stockholders per share, basic (in dollars per share)	$ (0.30)	$ (0.16)	$ (0.81)	$ (1.56)
Net loss attributable to common stockholders per share, diluted (in dollars per share)	$ (0.30)	$ (0.16)	$ (0.81)	$ (1.56)
Weighted-average shares used in calculating net loss per share, basic (in shares)	67,213,282	53,596,982	66,428,303	20,041,080
Weighted-average shares used in calculating net loss per share, diluted (in shares)	67,213,282	53,596,982	66,428,303	20,041,080
Product
Revenue:
Total revenue	$ 16,704	$ 14,103	$ 43,258	$ 33,893
Cost of sales:
Total cost of sales	4,797	3,463	11,832	8,467
Service
Revenue:
Total revenue	7,620	4,105	18,944	8,662
Cost of sales:
Total cost of sales	$ 4,114	$ 1,937	$ 9,778	$ 4,339