Commitments and Contingencies - Consulting Agreement - Additional Information (Detail) - Consulting Agreement [Member] - USD ($) |
1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |
---|---|---|---|---|
Jan. 31, 2014 |
Sep. 30, 2017 |
Sep. 30, 2017 |
Dec. 31, 2016 |
|
Commitments And Contingencies [Line Items] | ||||
Milestone payments | $ 0 | $ 0 | $ 0 | |
Research and development expense related to milestone expense | $ 0 | $ 0 | $ 0 | |
Clinical Development and Regulatory Milestones [Member] | ||||
Commitments And Contingencies [Line Items] | ||||
Shares of common stock for attaining milestones | 126,984 | |||
Milestone payments | $ 500,000 | |||
Milestone based issuance of shares | 39,681 | |||
Clinical Development and Regulatory Milestones [Member] | Maximum [Member] | ||||
Commitments And Contingencies [Line Items] | ||||
Expected milestone payments | $ 2,000,000 |