Collaboration and License Agreements - Schedule of Financial Information Related to Collaboration and License Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
ACCOUNTS RECEIVABLE	$ 4,141	$ 4,623
DEFERRED REVENUE, CURRENT	23,915	20,705
DEFERRED REVENUE, NET OF CURRENT	61,083	72,718
DEFERRED REVENUE, TOTAL	84,998	93,423
Restated Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
ACCOUNTS RECEIVABLE	583
DEFERRED REVENUE, CURRENT	7,821	12,164
DEFERRED REVENUE, NET OF CURRENT	31,286	32,784
DEFERRED REVENUE, TOTAL	39,107	44,948
Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
ACCOUNTS RECEIVABLE	631	275
DEFERRED REVENUE, CURRENT	13,694	6,141
DEFERRED REVENUE, NET OF CURRENT	28,597	36,934
DEFERRED REVENUE, TOTAL	42,291	43,075
Calico License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
ACCOUNTS RECEIVABLE	2,927	4,348
DEFERRED REVENUE, CURRENT	2,400	2,400
DEFERRED REVENUE, NET OF CURRENT	1,200	3,000
DEFERRED REVENUE, TOTAL	$ 3,600	$ 5,400