Commitments and Contingencies - Additional Information (Detail)	1 Months Ended						6 Months Ended
	Mar. 31, 2015 USD ($) ft²	Oct. 31, 2013 GBP (£)	Mar. 31, 2013 USD ($)	Dec. 31, 2010 USD ($)	May. 31, 2008 Claim	Jul. 31, 2006 Claim	Jun. 30, 2015 USD ($) Claim	Dec. 31, 2014 USD ($)
Commitment And Contingencies [Line Items]
Proceeds from the issuance of industrial revenue bonds							$ 5,000,000
Period of maturity							2014-08
Proceeds from sale of property, plant and equipment	$ 149,000						$ 148,713
Deferred rent under sublease agreement							$ 111,656	$ 85,925
Number of patents infringe claims of Neuralstem's activities | Claim					2	4
Number of patents expired | Claim							4
Patent Five [Member]
Commitment And Contingencies [Line Items]
Expiration year of patent							2016
Patent Six [Member]
Commitment And Contingencies [Line Items]
Expiration year of patent							2019
Pilot Manufacturing Facility [Member]
Commitment And Contingencies [Line Items]
Facility square-feet | ft²	21,000
Cell Processing Facility [Member]
Commitment And Contingencies [Line Items]
Facility square-feet | ft²	3,000
Prologis, L.P [Member]
Commitment And Contingencies [Line Items]
Term of lease			10 years
Rent over term of lease			$ 3,497,000
Deferred rent under sublease agreement							$ 388,000	391,000
BMR-Gateway Boulevard LLC [Member]
Commitment And Contingencies [Line Items]
Term of lease				11 years 6 months
Rent over term of lease				$ 17,869,000
Deferred rent under sublease agreement							$ 1,409,000	$ 1,429,000
Stem Cell Sciences (U.K.) Ltd [Member]
Commitment And Contingencies [Line Items]
Term of lease		3 years
Rental payments under the existing lease | £		£ 53,000
Lease termination date							Oct. 31, 2015