Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Additional Information (Detail)											3 Months Ended			6 Months Ended			10 Months Ended	12 Months Ended
	Jul. 13, 2017 USD ($)	Jun. 19, 2017 USD ($)	Jun. 14, 2017 $ / shares shares	May 08, 2017	Feb. 08, 2017 USD ($) shares	Aug. 24, 2016 USD ($) $ / shares shares	Jun. 20, 2016 shares	Apr. 29, 2016 USD ($) shares	Apr. 13, 2016 USD ($) $ / shares shares	Jan. 22, 2016	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) shares	Jun. 30, 2017 USD ($) Candidate Segment $ / shares shares	Mar. 31, 2017 USD ($) shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)
Organization And Summary Of Significant Accounting Policies [Line Items]
Date of incorporation														Sep. 24, 2012
State of Incorporation														Delaware
Highly liquid investments maturities														Three months or less
Common stock sold | shares								1,125,000	7,500,000
Cash proceeds from common stock issuance								$ 1,283,400	$ 7,754,286					$ 6,582,278		$ 9,918,750
Common stock, price per share | $ / shares									$ 1.25
Exercise price of warrant | $ / shares									$ 1.50			$ 10.00		$ 10.00			$ 10.00	$ 10.00
Warrants expiry date									Apr. 13, 2021					Apr. 13, 2021
Accumulated deficit												$ (70,670,801)		$ (70,670,801)			$ (70,670,801)	$ (70,670,801)	$ (60,277,267)
Number of operating segment | Segment														1
Ligand Note [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Required payment in cash for note obligation														$ 300,000
Loan and Security Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Required payment in cash for note obligation	$ 200,000
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.
Loan and Security Agreement [Member] | Ligand Note [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Loan and security agreement, maturity date										May 21, 2017
Third Amendment to Loan and Security Agreement [Member] | Ligand Note [Member]
Organization And Summary Of Significant Accounting Policies [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.
Third Amendment to Loan and Security Agreement [Member] | Ligand Note [Member] | Scenario Forecast [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Required payment in cash for note obligation											$ 200,000
Securities Purchase Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Public offering price per share and per warrant | $ / shares			$ 1.15
Securities Purchase Agreement [Member] | Private Placement and Registered Direct Offering [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Cash proceeds from common stock issuance		$ 3,900,000
Number of warrants issued for common stock | shares			0.75
Exercise price of warrant | $ / shares			$ 1.30
Warrants exercisable date			Dec. 19, 2017											Dec. 19, 2017
Warrants expiry date			Dec. 19, 2022											Dec. 19, 2022
Common Stock [Member] | Securities Purchase Agreement [Member] | Private Placement and Registered Direct Offering [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares			3,749,783
Maxim [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Cash proceeds from common stock issuance												$ 0	$ 0	$ 670,031	$ 670,031			$ 1,626,549
Maxim [Member] | Common Stock [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares												0	0	488,388	488,388			1,267,237
Maxim [Member] | Common Stock [Member] | Maximum [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Sale of common stock, shares | shares							3,748,726
Aspire Capital [Member] | Stock Purchase Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Stock purchase agreement termination date														Jun. 19, 2017
Aspire Capital [Member] | Common Stock [Member] | Stock Purchase Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares						333,333						0		1,326,991			1,476,991
Cash proceeds from common stock issuance												$ 0		$ 1,869,512			$ 2,042,762
Common stock sold aggregate purchase price						$ 500,000
Common stock purchase agreement term						30 months
Common stock, price per share | $ / shares						$ 1.50
Common stock issued as consideration for commitment fee | shares						336,116
Gross proceeds from common stock issuance												0		1,869,512			2,042,762
Aspire Capital [Member] | Common Stock [Member] | Maximum [Member] | Stock Purchase Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold aggregate purchase price						$ 12,500,000
PoC Capital, LLC [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Prepaid clinical study costs					$ 1,800,000							1,400,413		1,400,413			1,400,413	$ 1,400,413
PoC Capital, LLC [Member] | Common Stock [Member] | Stock Purchase Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares					1,286,173
PoC Capital, LLC [Member] | Common Stock [Member] | Stock Purchase Agreement [Member] | Clinical Studies [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold aggregate purchase price					$ 1,800,000
Ligand [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares									560,000
Accumulated deficit												$ (70,670,801)		$ (70,670,801)			$ (70,670,801)	$ (70,670,801)
Number Of Drug Candidates | Candidate														5
Ligand [Member] | Loan and Security Agreement [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Common stock sold | shares									960,000
Exercise price of warrant | $ / shares									$ 1.50
Warrants expiry date									Apr. 13, 2021					Apr. 13, 2021