Summary of Significant Accounting Policies - Addtional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Other Intangible Assets, Net		$ 900,000
Other Finite-Lived Intangible Assets, Gross		2,500,000
Cash	$ 5,965,000	9,375,000	$ 8,854,000
Depreciation	251,000	43,000
Research and Development Costs Expenses	5,500,000	5,500,000
Amortization	$ 160,000	$ 161,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	562,041	544,167
Net Income Loss	$ (7,023,000)	$ (6,750,000)
Retained Earnings (Accumulated Deficit), Total	$ (39,157,000)	$ (32,134,000)
Warrant
Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,277,784	595,118
Furniture and fixtures
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Computers and equipment
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Scientific equipment
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Leasehold improvements
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	Lesser of useful life or lease term
Preclinical Stage Biotechnology Company
Significant Accounting Policies [Line Items]
Development Project Service Evaluation Exchange Cost	$ 50,000
Technology Services Revenue	50,000
Jp Morgan Chase Bank
Significant Accounting Policies [Line Items]
Cash, FDIC Insured Amount	5,700,000	$ 9,100,000
Federal Deposit Insurance	250,000
Cash		9,400,000
Md Anderson
Significant Accounting Policies [Line Items]
Other Intangible Assets, Net	800,000
Other Finite-Lived Intangible Assets, Gross	2,500,000
Amortization of Intangible Assets	1,700,000
Technology Amortization Annually	$ 200,000	$ 200,000