Related Party Transaction (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($) ft²	Sep. 30, 2018 USD ($) ft²
Roivant Sciences Ltd \| Co-venturer \| Research and development services
Related Party Transaction [Line Items]
Expenses from transactions with related party	$ 0	$ 644,000
Genevant Sciences Corporation \| Equity Method Investee \| Research and development services
Related Party Transaction [Line Items]
Expenses from transactions with related party	$ 104,000	$ 227,000
Genevant Sciences Corporation \| Equity Method Investee \| Sublease, Burnaby Facility
Related Party Transaction [Line Items]
Area of sublease facility \| ft²	17,900	17,900
Genevant Sciences Corporation \| Equity Method Investee \| Administrative and transitional services
Related Party Transaction [Line Items]
Income from related party	$ 147,000	$ 318,000

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- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
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+ References

No definition available.

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 220
-Section S99
-Paragraph 1
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