Collaborative Arrangements - License Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized		$ 18,385	$ 21,906	$ 48,023	$ 49,808
Roche [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized		$ 100		$ 900
Roche [Member] | Milestone One [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of days for payment	45 days
Roche [Member] | Milestone Two [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of days for payment	60 days