Warrant Transactions - Additional Information (Details) - USD ($)		1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 22, 2015	Jun. 30, 2017	Mar. 31, 2017	May 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 19, 2010	Mar. 31, 2006
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)					0	675,000
Issuance of common stock (in shares)			9,200,000
Warrant modification					$ 0	$ 0	$ 425,538
Warrants exercised (in shares)					675,000	1,763,340
Allen, F. Stephen Series 2
Class of Warrant or Right [Line Items]
Issuance of warrants to purchase common stock (in shares)								1,000,000
Warrants repurchased (in shares)	50,000
Allen F. Stephen Series 2 and 3
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)						425,000
Exercise price of warrants (in dollars per share)				$ 3.55		$ 3.55		$ 3.55
Issuance of common stock (in shares)				425,000		275,000
Issuance of warrants to purchase common stock (in shares)									1,000,000
Warrants exercised (in shares)				425,000		275,000
OTA LLC Series 2
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)		$ 3.55
Issuance of common stock (in shares)		250,000
Warrants exercised (in shares)		250,000
Warberg WF IV LP | F. Stephen Allen
Class of Warrant or Right [Line Items]
Number of warrants sold (in shares)						250,000
OTA LLC Series 2 | Warberg WF IV LP | OTA LLC Series 2
Class of Warrant or Right [Line Items]
Number of warrants sold (in shares)						250,000
Minimum | Allen F. Stephen Series 2 and 3
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)									$ 4
Maximum | Allen F. Stephen Series 2 and 3
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)									$ 7
General and administrative | Allen, F. Stephen Series 2
Class of Warrant or Right [Line Items]
Warrant modification	$ 426,000