Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue
Total revenue	$ 85,071	$ 55,663	$ 38,448
Operating expenses
Cost of revenue	22,274	19,668	15,680
Research and development	70,705	39,157	31,995
Sales and marketing	38,453	24,486	16,765
General and administrative	30,332	20,409	15,949
Amortization of intangible assets	1,698	1,699	1,694
Restructuring			840
Total operating expenses	163,462	105,419	82,923
Loss from operations	(78,391)	(49,756)	(44,475)
Interest and other income, net	9,785	3,309	1,644
Net loss	(68,606)	(46,447)	(42,831)
Fair value adjustment to Series E-1 convertible preferred stock options	(964)	102	135
Net loss attributable to common shareholders	$ (69,570)	$ (46,345)	$ (42,696)
Net loss per share attributable to common shareholders, basic and diluted	$ (1.01)	$ (3.67)	$ (3.50)
Weighted-average shares used in computing net loss per share attributable to common shareholders, basic and diluted	69,165,315	12,629,778	12,196,998
Sequencing Revenue
Revenue
Total revenue	$ 43,519	$ 32,978	$ 22,759
Development Revenue
Revenue
Total revenue	$ 41,552	$ 22,685	$ 15,689