Income Taxes - Schedule of Significant Components of Company's Deferred Taxes (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued liabilities	$ 53,032	$ 59,333
Intangible assets	14,696,888	16,388,591
Net operating loss carryforwards	4,948,795	4,558,964
Share-based compensation	1,030,457	1,289,957
Credits	265,588
Other	6,679	3,017
Total deferred tax assets	21,001,439	22,299,862
Valuation Allowance	(20,775,747)	(22,115,992)
Total deferred tax assets, net of allowance	225,692	183,870
Deferred tax liabilities:
Debt conversion feature	(225,692)	(183,870)
Total deferred tax liabilities:	(225,692)	(183,870)
Net deferred tax assets (liabilities):	$ 0	$ 0