Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Total revenue	$ 19,250	$ 10,569	$ 37,878	$ 24,347
Cost of sales:
Total cost of sales	6,522	3,607	12,699	7,406
Gross profit	12,728	6,962	25,179	16,941
Operating expenses:
Research and development	13,535	11,843	26,562	22,819
General and administrative	11,725	4,193	20,692	8,190
Sales and marketing	5,317	3,076	10,923	6,310
Total operating expenses	30,577	19,112	58,177	37,319
Loss from operations	(17,849)	(12,150)	(32,998)	(20,378)
Other income (expense):
Interest expense	(356)	(356)	(710)	(713)
Interest income	43	47	109	198
Other income , net	34	37	53	62
Loss before income taxes	(18,128)	(12,422)	(33,546)	(20,831)
Provision for income taxes	26	8	43	24
Net loss and net comprehensive loss	(18,154)	(12,430)	(33,589)	(20,855)
Net loss and net comprehensive loss	$ (18,154)	$ (12,430)	$ (33,589)	$ (20,855)
Net loss attributable to common stockholders per share, basic (in dollars per share)	$ (0.27)	$ (4.25)	$ (0.51)	$ (7.29)
Net loss attributable to common stockholders per share, diluted (in dollars per share)	$ (0.27)	$ (4.25)	$ (0.51)	$ (7.29)
Weighted-average shares used in calculating net loss per share, basic (in shares)	66,790,755	3,109,545	66,029,307	3,078,756
Weighted-average shares used in calculating net loss per share, diluted (in shares)	66,790,755	3,109,545	66,029,307	3,078,756
Product
Revenue:
Total revenue	$ 13,021	$ 9,107	$ 26,554	$ 19,790
Cost of sales:
Total cost of sales	3,332	2,384	7,035	5,004
Service
Revenue:
Total revenue	6,229	1,462	11,324	4,557
Cost of sales:
Total cost of sales	$ 3,190	$ 1,223	$ 5,664	$ 2,402