Condensed Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue
Total revenue	$ 22,138	$ 11,568	$ 34,804	$ 21,283
Operating expenses
Cost of revenue	5,734	5,044	10,722	9,033
Research and development	16,527	9,452	29,010	18,307
Sales and marketing	8,897	5,329	16,714	10,376
General and administrative	6,662	4,632	13,666	9,175
Amortization of intangible assets	423	424	842	843
Total operating expenses	38,243	24,881	70,954	47,734
Loss from operations	(16,105)	(13,313)	(36,150)	(26,451)
Interest and other income, net	446	820	2,105	1,567
Net loss	(15,659)	(12,493)	(34,045)	(24,884)
Fair value adjustment to Series E-1 convertible preferred stock options	(710)	(2)	(964)	2
Net loss attributable to common shareholders	$ (16,369)	$ (12,495)	$ (35,009)	$ (24,882)
Net loss per share attributable to common shareholders, basic and diluted	$ (1.23)	$ (1.01)	$ (2.68)	$ (2.02)
Weighted-average shares used in computing net loss per share attributable to common shareholders, basic and diluted	13,279,324	12,385,888	13,074,692	12,334,227
Sequencing Revenue
Revenue
Total revenue	$ 11,865	$ 8,281	$ 17,948	$ 14,061
Development Revenue
Revenue
Total revenue	$ 10,273	$ 3,287	$ 16,856	$ 7,222