Liquidity, Going Concern and Management's Plans - Additional Information (Detail) - USD ($)			3 Months Ended		9 Months Ended
	Mar. 07, 2017	Jan. 27, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jul. 18, 2017	Dec. 31, 2016
Liquidity And Managements Plans [Line Items]
Net loss			$ (3,786,000)	$ (2,750,000)	$ (10,642,000)	$ (9,452,000)
Accumulated deficit			108,954,000		108,954,000			$ 98,312,000
Positive (deficit) in working capital			$ 4,700,000		4,700,000
Net cash used in operating activities					7,218,000	10,809,000
Shares issued for an investment (in shares)	1,666,666
Proceeds from issuance of common stock					$ 10,000,000	$ 70,000
Aspire Capital Fund, LLC [Member]
Liquidity And Managements Plans [Line Items]
Maximum commitment under stock purchase agreement		$ 17,000,000
Agreement term		30 months
Shares issued during period (in shares)	416,666	141,666
Proceeds from issuance of common stock	$ 2,000,000	$ 2,000,000
Essentialis, Inc. [Member]
Liquidity And Managements Plans [Line Items]
Proceeds from issuance of common stock	$ 8,000,000
NeoForce Holdings Inc. [Member]
Liquidity And Managements Plans [Line Items]
Total sales proceeds							$ 977,000