Discontinued Operations and Assets Held for Sale - Additional Information (Detail) - USD ($)		3 Months Ended
	Jul. 18, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock-based compensation expense, discontinued operation		$ 360,000	$ 185,000
OAHL [Member] | Capnia, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of shares issued		0
OAHL [Member] | Capnia, Inc. [Member] | Corporate Joint Venture [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment				$ 2,200,000
Discontinued Operations, Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock-based compensation expense, discontinued operation		$ 19,000	$ 45,000
NeoForce Holdings Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from the sale of business	$ 720,000