Sale of Business to Veracyte (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
	Feb. 27, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Gain on sale of business, net			$ 0	$ 48,871	$ 0
Veracyte
Business Acquisition [Line Items]
Gain on sale of business, net				48,900
Veracyte
Business Acquisition [Line Items]
Consideration transferred		$ 50,000
Cash paid		$ 40,000
Shares transferred		376,732
Value of shares transferred		10.0 million
Milestone payments	$ 10,000
Transaction costs		$ 1,100		$ 1,100