Equity - Additional Information (Detail) (USD $)	1 Months Ended			6 Months Ended	125 Months Ended	1 Months Ended	6 Months Ended			1 Months Ended	6 Months Ended
	Feb. 11, 2013	Jan. 23, 2013	Jan. 29, 2013	Jun. 30, 2013	Jun. 30, 2013	Feb. 28, 2013 ATM Agreement	Jun. 30, 2013 Common Stock	Jun. 30, 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 Common Stock	Jun. 30, 2013 $1.5 Million Purchase Agreement with Lincoln Park Common Stock
Equity Note [Line Items]
Common shares issued						167,618				125,000	975
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			3,578,288	53,032,085
Warrant term	4 years	5 years	5 years
Warrant exercise price	$ 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