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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- 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.

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- Definition

An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)(iii)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Number of shares issued under share-based payment arrangement.

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-Publisher FASB
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-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Intrinsic value of vested award under share-based payment arrangement. Excludes share and unit options.

+ References

No definition available.

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Stock-based compensation - Narrative (Detail) $ in Thousands			3 Months Ended	12 Months Ended
	Nov. 04, 2021 USD ($) shares	Feb. 01, 2021 shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio			0.3333	0.3333			0.3333
Incremental fair value of equity award modification	$ 1,300			$ 1,500
Stock-based compensation expense				41,040	$ 54,629	$ 60,997
Intrinsic value of restricted stock units vested				5,500
Performance and service condition based restricted stock unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				600	400
Unrecognized stock- based compensation expense related to unvested stock options, restricted stock awards and employee stock purchase plan			$ 600	600
Share-based compensation arrangement by share-based payment award, shares issued in period (less than) (in shares) \| shares	17,387
Performance and service condition based restricted stock unit \| Bluebird Bio
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, shares issued in period (less than) (in shares) \| shares		27,000
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock- based compensation expense related to unvested stock options, restricted stock awards and employee stock purchase plan			17,900	$ 17,900
Expected weighted-average period related to unvested stock options, restricted stock awards and employee stock purchase plan				2 years 3 months 18 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 22,983	$ 21,414	$ 19,185
Unrecognized stock- based compensation expense related to unvested stock options, restricted stock awards and employee stock purchase plan			20,900	$ 20,900
Expected weighted-average period related to unvested stock options, restricted stock awards and employee stock purchase plan				1 year 10 months 24 days
Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock- based compensation expense related to unvested stock options, restricted stock awards and employee stock purchase plan			$ 600	$ 600
Expected weighted-average period related to unvested stock options, restricted stock awards and employee stock purchase plan				1 year 1 month 6 days
2021 Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, shares issued in period (less than) (in shares) \| shares			200,000
2021 Stock Option and Incentive Plan \| Unrestricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 6,500
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, shares issued in period (less than) (in shares) \| shares				100,000