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Share Capital - Additional Information (Detail)	1 Months Ended						12 Months Ended
Share Capital - Additional Information (Detail)	Jan. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Jul. 31, 2020 USD ($) $ / shares shares	Nov. 30, 2019 USD ($) $ / shares shares	Aug. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2021 SFr / shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 SFr / shares	Dec. 31, 2020 USD ($) shares
Class of Stock [Line Items]
Common stock, shares authorized \| shares											145,364,335		115,172,786
Common shares, par value \| SFr / shares										SFr 0.03		SFr 0.03
Capital reserved for future issuance \| shares											5,038,262
Proceeds from issuance of common shares							$ 213,267,000	$ 982,289,000	$ 415,019,000
Common Stock, Voting Rights							one vote for each common share
Dividends declared and paid							$ 0
Underwritten Public Offering [Member]
Class of Stock [Line Items]
Common shares sold \| shares			7,400,000	4,900,000
Common shares price per share \| $ / shares			$ 70.00	$ 64.50
Proceeds from issuance of common shares			$ 484,800,000	$ 297,400,000
Equity issuance costs			$ 32,500,000	$ 17,800,000
Payments of stamp taxes related to securities									$ 3,000,000.0
2018 ATM [Member] \| Sales Agreement With Jefferies LLC [Member]
Class of Stock [Line Items]
Common shares sold \| shares									2,800,000
Proceeds from issuance of common shares									$ 120,600,000
Equity issuance costs									4,400,000
Payments of stamp taxes related to securities								$ 300,000	$ 900,000
Average issue price of common shares \| $ / shares									$ 44.38
Accrued stamp taxes									$ 300,000
2018 ATM [Member] \| Sales Agreement With Jefferies LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds						$ 125,000,000.0
2019 ATM [Member] \| Sales Agreement With Jefferies LLC [Member]
Class of Stock [Line Items]
Common shares sold \| shares								2,200,000
Proceeds from issuance of common shares								$ 195,500,000
Equity issuance costs								$ 4,500,000
Average issue price of common shares \| $ / shares								$ 89.47
2019 ATM [Member] \| Sales Agreement With Jefferies LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds					$ 200,000,000.0
2020 ATM [Member] \| Sales Agreement With Jefferies LLC [Member]
Class of Stock [Line Items]
Common shares sold \| shares	300,000							1,800,000
Proceeds from issuance of common shares	$ 46,700,000							$ 298,000,000.0
Equity issuance costs	$ 700,000							4,500,000
Payments of stamp taxes related to securities							$ 500,000	$ 4,900,000
Payable of stamp taxes related to securities											$ 4,000,000.0		$ 4,000,000.0
Average issue price of common shares \| $ / shares	$ 162.46							$ 169.57
2020 ATM [Member] \| Sales Agreement With Jefferies LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds		$ 350,000.0
2021 ATM [Member] \| Sales Agreement With Jefferies LLC [Member]
Class of Stock [Line Items]
Common shares sold \| shares							1,100,000
Proceeds from issuance of common shares							$ 177,800,000
Equity issuance costs							2,400,000
Payments of stamp taxes related to securities							$ 1,800,000
Average issue price of common shares \| $ / shares							$ 169.82
2021 ATM [Member] \| Sales Agreement With Jefferies LLC [Member] \| Maximum [Member]
Class of Stock [Line Items]
Aggregate estimated gross proceeds	$ 600,000.0