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License agreement.

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License Maintenance Fees

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Milestone payment.

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Milestone payments.

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- Definition

Option fee.

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Payments upon closing of initial public offering.

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- Definition

Represents the amount of the upfront license fees.

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Upfront payment paid in cash.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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License Agreements - Additional Information (Detail) $ in Thousands					1 Months Ended	12 Months Ended
	Oct. 02, 2017 USD ($)	Nov. 17, 2016 USD ($)	Jan. 27, 2016 USD ($) shares	Jan. 27, 2016 CAD ($)	Aug. 31, 2017 USD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Jan. 27, 2016 CAD ($) shares
License Agreement [Line Items]
Research and development						$ 35,095,000	$ 15,191,000
Common stock, shares issued \| shares						23,959,903	2,581,474
Fair value of shares issued						$ 104,013,000
Preferred stock issued \| shares						0	0
UHN Agreement [Member] \| Fabry License Agreement [Member]
License Agreement [Line Items]
Option fee								$ 20
Upfront license fee				$ 75
Milestone payments				2,450
Research and development						$ 15,000	$ 16,000
UHN Agreement [Member] \| Interleukin 12 License Agreement [Member]
License Agreement [Line Items]
Upfront license fee				264
Milestone payments				19,275
Research and development						41,000	151,000
Common stock, shares issued \| shares			1,161,665					1,161,665
Fair value of shares issued			$ 480
Payments upon closing of an initial public offering			2,000,000
Fair value of derivative liability			$ 49,000
Annual maintenance fees				$ 19,275
BioMarin Pharmaceutical Inc [Member]
License Agreement [Line Items]
Upfront license fee					$ 500,000
Milestone payments						13,000,000
Research and development							1,000,000
Upfront cash payment							500,000
Expenses related to license						0
BioMarin Pharmaceutical Inc [Member] \| Series B Preferred Stock [Member]
License Agreement [Line Items]
Research and development							500,000
Preferred stock issued \| shares					233,765
GenStem Therapeutics Inc [Member]
License Agreement [Line Items]
Upfront license fee	$ 1,000,000
Research and development							1,000,000
Expenses related to license						0
Milestone payments	$ 16,000,000
Lund University Rights Holders Agreement [Member]
License Agreement [Line Items]
Expenses related to license						$ 0	$ 0
Milestone payments		$ 550