Liquidity and Management's Plans (Detail) - USD ($)			9 Months Ended
	Aug. 16, 2017	Jan. 23, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Liquidity and Managements Plans [Line Items]
Gross proceeds before deducting estimate offering expenses		$ 19,000,000
Offering costs		$ 2,500,000
Common stock warrants	2,575,000		599,670
Proceeds from warrants exercised			$ 3,334,176
Cash and cash equivalents			23,433,297	$ 3,310,787	$ 6,841,547	$ 7,927,240
Series B convertible preferred stock
Liquidity and Managements Plans [Line Items]
Proceeds from Issuance of Convertible Preferred Stock	$ 20,000,000		$ 18,400,000
Underwriting discounts and commissions and offering expenses	$ 2,000,000