Balance Sheet Components - Other Assets (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Feb. 28, 2019	Apr. 30, 2016	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Apr. 30, 2019	Dec. 31, 2018	Aug. 31, 2017	Aug. 08, 2017
Balance Sheet Components [Line Items]
Agreement term		4 years
Total consideration		$ 3,200
Deferred costs included in other long-term assets			$ 600		$ 600			$ 1,000
Amortization of deferred costs					200
Cost of revenues			$ 41,382	$ 39,204	$ 82,987	$ 78,259
Common stock, shares issued			70,035,000		70,035,000			62,083,000
Amortization of debt discount			$ 100	$ 100	$ 215	195
Debt discount			1,000		1,000
Noncurrent assets			13,091		13,091			$ 3,317
2017 Term Loan
Balance Sheet Components [Line Items]
Common stock, shares issued							25,000		300,000
Remaining borrowing capacity								$ 50,000	$ 50,000	$ 25,000
2017 Term Loan | Direct reduction from outstanding debt balance
Balance Sheet Components [Line Items]
Debt instrument, fee amount										$ 2,000
2017 Term Loan | Noncurrent assets
Balance Sheet Components [Line Items]
Debt instrument, fee amount			1,200		1,200				$ 1,200
Health Insurance Carrier Agreement
Balance Sheet Components [Line Items]
Cost of revenues					400	$ 400
Evercord | Storage services
Balance Sheet Components [Line Items]
Noncurrent assets			300		300
BGI
Balance Sheet Components [Line Items]
Agreement term	10 years
BGI | Sequencing products and services
Balance Sheet Components [Line Items]
Noncurrent assets			$ 10,000		$ 10,000