Commitments and Contingencies - Consulting Agreement - Additional Information (Detail) - Consulting Agreement [Member]	1 Months Ended			3 Months Ended			9 Months Ended
	Jun. 30, 2015 Milestone	Mar. 31, 2015 Milestone	Jan. 31, 2014 USD ($) shares	Sep. 30, 2016 USD ($)	Jun. 30, 2015 USD ($) shares	Mar. 31, 2015 USD ($) shares	Sep. 30, 2016 USD ($)
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense				$ 0			$ 0
Milestone payments				$ 0			$ 0
Clinical Development and Regulatory Milestones [Member]
Commitments And Contingencies [Line Items]
Milestone payment			$ 2,000,000
Shares of common stock for attaining milestones | shares			126,984
Second Clinical Development Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense						$ 600,000
Milestone payments						200,000
Payments for stock issued upon reaching a milestone						$ 400,000
Milestone based share compensation, shares issued | shares						7,936
Milestones achieved | Milestone		1
Third Clinical Development Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense					$ 1,100,000
Milestone payments					300,000
Payments for stock issued upon reaching a milestone					$ 800,000
Milestone based share compensation, shares issued | shares					15,873
Milestones achieved | Milestone	1