Equity - Additional Information (Detail) (USD $)	1 Months Ended				3 Months Ended	122 Months Ended	1 Months Ended			1 Months Ended
	Feb. 28, 2013	Feb. 11, 2013	Jan. 23, 2013	Jan. 29, 2013	Mar. 31, 2013	Mar. 31, 2013	Feb. 28, 2013 ATM Agreement	Mar. 31, 2013 $1.5 Million Purchase Agreement with Lincoln Park	Jan. 31, 2013 $1.5 Million Purchase Agreement with Lincoln Park	Jan. 31, 2013 $1.5 Million Purchase Agreement with Lincoln Park Issuance of Equity
Equity Note [Line Items]
Common shares issued							167,618			125,000
Purchase agreement, aggregate shares opexa has right to sell					$ 16,500,000	$ 16,500,000		$ 1,500,000	$ 1,500,000
Net proceeds from shares sold							536,417			142,400
Common stock issued as fee										975
Common shares issued, note conversion					365,263
Common shares issued		1,083,334
Warrants settlement ratio		Each unit consisting of one share of common stock and a warrant to purchase half (0.5) a share of common stock
Share issue to private offering, price per share		$ 3.00
Proceeds from issuance of common stocks and warrants, net		3,250,002			3,623,738	53,077,535
Warrant term	4 years	4 years	5 years	5 years
Warrant exercise price	$ 3.00	$ 3.00	$ 1.24	$ 1.21
Commission rate on gross proceed for common stock sold		6.00%
Amount netted against additional paid in capital as stock offering costs					$ 350,530