Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) Performance_Obligation Segment shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2014 USD ($) $ / shares shares
Significant Accounting Policies [Line Items]
Restricted cash	$ 2,138,000	$ 61,000
Unbilled receivables	2,400,000	400,000
Impairment of goodwill	0
Impairment losses on intangible assets	$ 0
Warrants issued to purchase stock | shares	56,875
Fair value adjustment of warrants	$ 2,266,000	(6,000)	$ (23,000)
Advertising expenses	$ 6,600,000	$ 3,500,000	$ 1,800,000
Number of operating segment | Segment	1
Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Cumulative impact to accumulated deficit	$ 100,000
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Operating leases future minimum lease payments	$ 54,100,000
Sequencing Revenue
Significant Accounting Policies [Line Items]
Number of revenue performance obligations | Performance_Obligation	2
Sequencing Revenue From Coverage Policy
Significant Accounting Policies [Line Items]
Revenue recognized	$ 1,600,000
Sequencing Revenue From Test Deliver
Significant Accounting Policies [Line Items]
Revenue recognized	400,000
Series C Convertible Preferred Stock
Significant Accounting Policies [Line Items]
Warrants issued to purchase stock | shares				56,875
Weighted-average exercise price of warrants | $ / shares				$ 2.64
Line of credit facility				$ 5,000,000.0
Fair value adjustment of warrants	2,300,000
Financial liabilities	2,600,000
Property and Equipment, Net
Significant Accounting Policies [Line Items]
Building costs	36,600,000
Additional Paid In Capital
Significant Accounting Policies [Line Items]
Deferred offering costs	$ 5,000,000.0