Summary of Significant Accounting Policies - Addtional Information (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Other Intangible Assets, Net					$ 1,100,000					$ 1,100,000
Other Finite-Lived Intangible Assets, Gross					2,500,000					2,500,000
Research and Development									$ 5,474,000	3,020,000	$ 1,630,000
Cash	$ 9,375,000				8,854,000				9,375,000	8,854,000	13,859,000	$ 3,552,000
Depreciation									43,000	41,000	10,000
Amortization									$ 161,000	$ 161,000	$ 161,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									5,441,673	5,078,611	4,734,861
Net Income Loss	(1,371,000)	$ (1,570,000)	$ (1,942,000)	$ (1,867,000)	(1,458,000)	$ (1,508,000)	$ (1,126,000)	$ (1,375,000)	$ (6,750,000)	$ (5,467,000)	$ (4,519,000)
Retained Earnings (Accumulated Deficit), Total	(32,134,000)				(25,384,000)				$ (32,134,000)	$ (25,384,000)
Warrant
Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									5,951,176	2,760,000	2,760,000
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
Research and Development Expense
Significant Accounting Policies [Line Items]
Technology Amortization Monthly	1,600,000								$ 1,600,000
Preclinical Stage Biotechnology Company
Significant Accounting Policies [Line Items]
Development Project Service Evaluation Exchange Cost									50,000
Technology Services Revenue									13,000
Jp Morgan Chase Bank
Significant Accounting Policies [Line Items]
Cash, FDIC Insured Amount	9,100,000				8,600,000				9,100,000	$ 8,600,000
Federal Deposit Insurance									250,000
Cash					$ 8,900,000					8,900,000
Md Anderson
Significant Accounting Policies [Line Items]
Other Intangible Assets, Net	900,000								900,000
Other Finite-Lived Intangible Assets, Gross	2,500,000								2,500,000
Amortization of Intangible Assets									1,600,000
License Expenses											$ 100,000
Clinical Trial Expense											100,000
Research and Development											100,000
Technology Cost Paid In cash	$ 800,000								$ 800,000
Technology Cost Paid In Shares	3,100,000								3,100,000
Technology Cost Paid In Shares Value	$ 2,400,000								$ 2,400,000
Technology Impairment Charge	700,000								700,000
Technology Amortization Monthly	$ 200,000								200,000
Research and Development Costs Expenses									$ 5,500,000	3,000,000
Equity Method Investment, Ownership Percentage	5.00%								5.00%
Related Party
Significant Accounting Policies [Line Items]
License Maintenance Fees											100,000
Research and Development									$ 0	$ 0	197,000
Related Party | Research and Development Expense
Significant Accounting Policies [Line Items]
Sirna Patent Technology License											$ 31,000