Subsequent Events	6 Months Ended
Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsThe Company entered into two new agreements in July 2020 to lease additional office and laboratory space. The lease agreements each have a target commencement date in the first half of fiscal year 2021, with estimated aggregate base rent payments of $239.5 million over the weighted average estimated lease term of 11.5 years. One of the lease agreements provides an option to renew the lease term for an additional ten years. The Company is currently evaluating the accounting for such leases.

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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