Sub lease commencement date.

No definition available.

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Period Type:	duration

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

+ References

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Balance Type:	debit
Period Type:	instant

- Definition

Indicates (true false) whether sublessee has option to extend operating sublease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Balance Type:	na
Period Type:	duration

- Definition

Description of terms and conditions of option to extend operating sublease.

+ References

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

+ References

No definition available.

+ Details

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- Definition

Amount of selling, general and administrative expenses resulting from transactions, excluding transactions that are eliminated in consolidated or combined financial statements, with related party.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Balance Type:	credit
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- Definition

Amount of sublease income excluding finance and operating lease expense.

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- Details

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- Details

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Namespace Prefix:
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Period Type:

- Details

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Related Party Transactions - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Feb. 29, 2016
Related Party Transaction [Line Items]
Collaboration revenue - related party		$ 4,840,000	$ 8,684,000	$ 21,909,000	$ 16,721,000
Sublease income		439,000		439,000
Nestlé Health Science [Member]
Related Party Transaction [Line Items]
Collaboration revenue - related party		4,840,000	8,684,000	21,909,000	16,721,000
Deferred revenue		115,350,000		115,350,000		$ 120,000,000
Payments under agreements with related party		0	$ 0	0	$ 0
Due from related party for the reimbursement of development costs		0		$ 0
Flagship Pioneering [Member] \| Sublease Agreement [Member]
Related Party Transaction [Line Items]
Sub lease commencement date	2019-07
Lessee, operating sublease, existence of option to extend				false
Lessee, operating sublease, option to extend, description				The term of the sublease agreement commenced in July 2019 and ends on the last day of the 24th calendar month following commencement, with no option to extend
Cash received from related party transaction		409,000		$ 409,000
Flagship Pioneering [Member] \| Sublease Agreement [Member] \| Other Income [Member]
Related Party Transaction [Line Items]
Sublease income		$ 439,000		$ 439,000