Subsequent Events	9 Months Ended
Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent events In October 2021, the Company entered into an Option and License Agreement with Beam Therapeutics Inc. (Beam), pursuant to which Beam granted to the Company a non-exclusive license to use Beam’s proprietary CRISPR Cas12b nuclease editing technology to research, develop and commercialize engineered cell therapy products that (i) are directed to certain antigen targets, with respect to the Company’s allogeneic T cell programs, or (ii) comprise certain human cell types, with respect to the Company’s stem cell-derived programs. Pursuant to the agreement, the Company made an upfront payment of $50.0 million to Beam. Additionally, the Company will be obligated to pay to Beam up to $65.0 million for each licensed product in specified developmental and commercial milestone payments and royalties on licensed products. A member of the Company’s board of directors is a beneficial owner of greater than 10% of the outstanding shares of Beam and is affiliated with a member of the board of directors of Beam.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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