Stock Options and Warrants - Warrants Issued with Common Stock - Additional Information (Detail) - $ / shares			3 Months Ended
	Mar. 12, 2013	Jan. 22, 2013	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock sold	33,334	67,500
Warrants outstanding converted into common stock	16,667	33,750
Warrants exercisable price	$ 30.00	$ 30.00	$ 1.75
Warrant term		5 years
Expiration date of warrants			Jan. 31, 2018
Co-Chairman and Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding converted into common stock	1,667
Warrant term	5 years
Expiration date of warrants			Mar. 31, 2018