Balance Sheet Components - Other Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Apr. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Apr. 30, 2019	Aug. 31, 2017	Aug. 08, 2017
Balance Sheet Components [Line Items]
Common stock, shares issued	79,717,000		79,717,000			78,005,000
Cost of revenues	$ 42,731	$ 41,382	$ 84,251	$ 82,987
Amortization of debt discount and issuance cost		215	2,180
Noncurrent assets	12,357		12,357			$ 12,476
Convertible Notes
Balance Sheet Components [Line Items]
Debt discount					$ 8,600
Evercord
Balance Sheet Components [Line Items]
Net collections			1,000
Credit loss expense			1,200
Evercord | Contingent consideration
Balance Sheet Components [Line Items]
Total consideration						$ 4,700
Noncurrent assets
Balance Sheet Components [Line Items]
Debt discount	0		0
Long-term Debt
Balance Sheet Components [Line Items]
Debt discount	900		900
2017 Term Loan
Balance Sheet Components [Line Items]
Common stock, shares issued								25,000	300,000
Remaining borrowing capacity	50,000		50,000						$ 50,000	$ 25,000
Amortization of debt discount and issuance cost		$ 100	100	$ 200
2017 Term Loan | Noncurrent assets
Balance Sheet Components [Line Items]
Debt instrument, fee amount									$ 1,200
Evercord | Contingent consideration
Balance Sheet Components [Line Items]
Accounts receivable	2,500		2,500
BGI | Sequencing products and services
Balance Sheet Components [Line Items]
Noncurrent assets	$ 10,000		$ 10,000				$ 10,000