Commitments and Contingencies - University of California License Agreement - Additional Information (Detail) - University of California License Agreement [Member]	1 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	May 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Milestone	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense			$ 0		$ 0	$ 0
Milestone payments			$ 0		$ 0	$ 0
Upfront payment	$ 50,000
Annual license maintenance fee				$ 15,000
After The Effective Date [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum		27 years
After The First Sale [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum		15 years
Clinical Development [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense				100,000
Milestone payments				$ 100,000
Milestones achieved | Milestone				3
Clinical Development [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Milestone payments		$ 100,000
Percentage of net sales paid as royalties		1.00%
Regulatory Milestones [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	700,000
Sales Milestones [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	$ 2,000,000