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Net Loss Per Share - Additional Information (Detail) - shares			3 Months Ended	12 Months Ended
	Oct. 10, 2017	Jul. 01, 2017	Mar. 31, 2018	Dec. 31, 2017
JGB Debt [Member]
Schedule of Net Income (Loss) Per Share [Line Items]
Shares issued upon conversion		1,022,544	6,415,039	6,415,039
Underwritten Public Offering [Member]
Schedule of Net Income (Loss) Per Share [Line Items]
Common stock shares issued	4,992,840

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- Definition

Schedule of net income (loss) per share.

+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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