Share-Based Compensation - Summary of Stock Option Activity (Detail) - Stock Option [Member]	6 Months Ended
Jun. 30, 2019 shares
Number of Shares
Outstanding, Beginning Balance	2,297,810
Granted	932,734
Exercised	(53,368)
Forfeited	(78,695)
Outstanding Ending Balance	3,098,481
2017 Plan [Member]
Number of Shares
Outstanding, Beginning Balance	2,297,810
Granted	860,434
Exercised	(53,368)
Forfeited	(78,695)
Outstanding Ending Balance	3,026,181
2019 Inducement Plan [Member]
Number of Shares
Granted	72,300
Outstanding Ending Balance	72,300

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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Number of share options (or share units) exercised during the current period.

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