Convertible Notes Payable - Additional Information (Detail) - USD ($)						3 Months Ended				6 Months Ended
	Jul. 13, 2017	May 08, 2017	Apr. 29, 2016	Apr. 13, 2016	Jan. 22, 2016	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jan. 21, 2016	May 21, 2014
Debt Instrument [Line Items]
Date of registration rights agreement amendment										Jan. 22, 2016
Proceeds from issuances of common stock, net of underwriting discounts and commissions			$ 1,283,400	$ 7,754,286						$ 6,582,278	$ 9,918,750
Underwriting discounts, commissions and other offering expenses			$ 111,600	$ 1,631,964
Repayments of notes payable in stock											1,200,000
Common stock sold			1,125,000	7,500,000
Warrants sold				7,500,000
Warrants exercise price per share of common stock				$ 1.50			$ 10.00			$ 10.00
Warrants expiry date				Apr. 13, 2021						Apr. 13, 2021
Increase in fair value of debt conversion feature liability							$ 570,676	$ 412,050		$ 848,374	508,597
Amortization of debt discount							336,656	524,977		767,883	925,634
Ligand [Member]
Debt Instrument [Line Items]
Common stock sold				560,000
Warrants sold				560,000
Ligand Note [Member]
Debt Instrument [Line Items]
Note obligation							1,500,000			1,500,000
Next financing payment to be paid in cash										300,000
Repayments of notes payable in stock										1,200,000
Interest expense							24,439	25,423		48,878	56,673
Amortization of debt discount							336,656	524,977		767,883	925,634
Other income related to debt conversion feature							570,676	$ 412,050		$ 848,374	508,597
Loan and Security Agreement [Member]
Debt Instrument [Line Items]
Aggregate net proceeds from issue of equity securities					$ 2,000,000
Next financing payment to be paid in cash	$ 200,000
Shares issued price per share					$ 8.00
Debt Instrument repayment, description										Each $1.00 of the $1,500,000 payment reduced the amount of accrued and unpaid interest and then unpaid principal amount of the loans under the Ligand Note by $0.50.
Additional repayment notice period within closing of the next financing										180 days
Additional repayment notice period after the closing of the next financing										180 days
Weighted average closing price of common stock period										30 days
Loan and Security Agreement [Member] | Ligand [Member]
Debt Instrument [Line Items]
Repayments of notes payable in stock				$ 1,200,000
Common stock sold				960,000
Warrants sold				960,000
Warrants exercise price per share of common stock				$ 1.50
Warrants expiry date				Apr. 13, 2021						Apr. 13, 2021
Loan and Security Agreement [Member] | Minimum [Member]
Debt Instrument [Line Items]
Beneficial ownership of company's common stock		49.90%		49.90%
Loan and Security Agreement [Member] | Ligand Note [Member]
Debt Instrument [Line Items]
Loan and security agreement, maturity date					May 21, 2017
Note obligation					$ 1,500,000
Loan and Security Agreement [Member] | Ligand Note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Next financing payment to be paid in cash					$ 300,000
Debt Conversion Feature Liability [Member]
Debt Instrument [Line Items]
Adjustments resulting from modification of debt							$ (1,011,478)			$ (1,011,478)	$ 575,685
Debt Conversion Feature Liability [Member] | Ligand Note [Member]
Debt Instrument [Line Items]
Adjustments resulting from modification of debt									$ 575,685
Third Amendment to Loan and Security Agreement [Member] | Ligand Note [Member]
Debt Instrument [Line Items]
Loan and security agreement, maturity date		May 21, 2018
Debt Instrument repayment, description		Each $1.00 of value of the Required Repayment will reduce the amount of accrued and unpaid interest and then unpaid principal amount on the Loans by $0.50.								Each $1.00 of value of the Required Repayment will reduce the amount of accrued and unpaid interest and then unpaid principal amount on the Loans by $0.50.
Increase in fair value of debt conversion feature liability		$ 1,000,000
Third Amendment to Loan and Security Agreement [Member] | Ligand Note [Member] | Scenario Forecast [Member]
Debt Instrument [Line Items]
Next financing payment to be paid in cash						$ 200,000
Ligand Debt
Debt Instrument [Line Items]
Loan and security agreement													$ 2,500,000
Fixed accrued interest rate					2.50%							5.00%
Fixed accrued interest rate of default loan										8.00%
Loan and security agreement, maturity date										May 21, 2018
Note conversion, principal amount of loan plus all accrued and previously unpaid interest							200.00%			200.00%