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Net Loss per Share - Schedule of Potentially Common Shares Excluded from Calculation of Net Loss Per share (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Unvested Restricted Common Stock Awards
Potentially Common Shares Excluded from Calculation of Net Loss Per share	118,679	375,479
Stock Options
Potentially Common Shares Excluded from Calculation of Net Loss Per share	1,739,884	1,267,221

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

+ Details

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