Stock Options and Warrants - Additional Information (Detail)

v3.10.0.1

Stock Options and Warrants - Additional Information (Detail) - USD ($)												1 Months Ended			12 Months Ended
	May 31, 2018	May 22, 2018	Mar. 23, 2018	Jan. 23, 2018	Nov. 24, 2017	Oct. 11, 2017	Sep. 08, 2017	Jun. 14, 2017	Feb. 28, 2017	Jan. 31, 2017	Dec. 12, 2016	Jan. 31, 2018	Jan. 31, 2017	Sep. 30, 2016	May 31, 2018	May 31, 2017	May 31, 2016	Nov. 30, 2017	Aug. 24, 2017	Jun. 19, 2017	Jun. 30, 2016	Mar. 31, 2016	Feb. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options grant date fair value															$ 0.25
Warrants to purchase common shares, shares			3,027,263
Common Stock issued	216,881,790														216,881,790	149,468,244
Proceeds from Issuance of Common Stock															$ 8,990,000
Inducement interest related to warrant extensions			$ 400,000										$ 72,000		826,252	$ 72,437	$ 866,713
Proceeds From Exercises of Warrant			1,500,000												3,161,131	397,883	548,619
Solicitation fees			$ 73,000
Extended expiration date of warrants													May 31, 2017
Compensation expense															$ 1,290,777	$ 1,204,791	$ 2,353,194
Warrants Determined to Extend Expiration Dates
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares										6,310,667			6,310,667				6,300,000
Term of warrants																	2 years
Exercise price of warrants, per share										$ 1.00			$ 1.00				$ 1.00
Inducement interest related to warrant extensions																	$ 867,000
Extended expiration date of warrants													May 31, 2017
October Twenty Sixteen Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants										2			2
Warrants exercisable period, closing month/year													2016-10
December Twenty Sixteen Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares										186,667			186,667
Number of warrants										1			1
Warrants exercisable period, closing month/year													2016-12
January Twenty Seventeen Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares										160,000			160,000
Number of warrants										1			1
Warrants exercisable period, closing date													Jan. 15, 2017
2017 Short Term Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares												7,718,010				383,333				383,333
Term of warrants																5 years
Exercise price of warrants, per share																$ 1.35
Minimum | 2017 Short Term Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share								$ 1.00
Warrant covering common stock shares purchased, percentage								25.00%
Maximum | 2017 Short Term Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share								$ 1.35
Warrant covering common stock shares purchased, percentage								50.00%
Placement Agent
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares		315,200		245,681		150,461	213,573		453,652	122,799			122,799	1,066,667
Term of warrants		5 years		5 years		5 years	5 years		5 years	5 years			5 years	5 years
Exercise price of warrants, per share		$ 0.55		$ 0.55		$ 0.715	$ 0.825		$ 0.825	$ 0.825			$ 0.825	$ 0.825
Placement Agent | 2017 Short Term Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares	350,766														350,766
Term of warrants	5 years														5 years
Exercise price of warrants, per share	$ 0.825														$ 0.825
Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share	$ 0.50														$ 0.50
Common Stock issued	3,295,000														3,295,000
Proceeds from Issuance of Common Stock															$ 1,600,000
Subscription Agreements
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares		4,640,000		3,071,014		940,380	1,668,163		2,835,323	767,498		7,718,010	767,498
Term of warrants		5 years		5 years		5 years	5 years		5 years	5 years		5 years	5 years
Exercise price of warrants, per share		$ 0.75		$ 0.75		$ 0.75	$ 1.00		$ 1.00	$ 1.00		$ 0.75	$ 1.00
Proceeds from Issuance of Common Stock		$ 2,100,000		$ 1,400,000		$ 1,100,000	$ 2,300,000		$ 3,800,000	$ 1,000,000
Inducement interest related to warrant extensions												$ 2,400,000
Subscription Agreements | 2017 Short Term Convertible Notes | Detachable Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share												$ 0.75
Securities Purchase Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares											2,000,000			6,666,667
Term of warrants											5 years			5 years
Exercise price of warrants, per share											$ 1.00			$ 1.00
Proceeds from Issuance of Common Stock											$ 3,000,000			$ 9,000,000
Securities Purchase Agreement | 2017 Short Term Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares	3,258,990														3,258,990
Term of warrants	5 years														5 years
Exercise price of warrants, per share	$ 1.00														$ 1.00
Securities Purchase Agreement | Placement Agent
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares														1,066,667
Term of warrants														5 years
Exercise price of warrants, per share														$ 0.825
Securities Purchase Agreement | Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares														6,666,667
Term of warrants														5 years
Exercise price of warrants, per share														$ 1.00
Make-Whole Securities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares																		251,504
Term of warrants																		5 years
Exercise price of warrants, per share																		$ 0.75
Make-Whole Securities | Placement Agent
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares	26,702														26,702			26,702
Term of warrants																		5 years
Exercise price of warrants, per share							$ 0.715											$ 0.715
Make-Whole Securities | Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share							$ 0.75
Before Inducement | Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share	$ 1.00														$ 1.00
Class of warrant or right expiration date															Jun. 30, 2017
Private Equity Offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares	35,286,904														35,286,904						182,375
Term of warrants	5 years														5 years	5 years					5 years
Exercise price of warrants, per share	$ 0.75														$ 0.75	$ 1.00					$ 1.35
Warrant covering common stock shares purchased, percentage															100.00%	25.00%
Proceeds From Exercises of Warrant																$ 398,000
Warrants to purchase common shares, shares																774,097
Private Equity Offering | Non Cash Exercise
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares																138,864
Private Equity Offering | Exercise Price 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share																$ 0.50
Private Equity Offering | Exercise Price 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share																0.75
Private Equity Offering | Exercise Price 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share																$ 0.75
Private Equity Offering | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share																	$ 0.75
Warrant covering common stock shares purchased, percentage																	50.00%
Private Equity Offering | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share																	$ 1.00
Warrant covering common stock shares purchased, percentage																	25.00%
Private Equity Offering | Placement Agent
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares	2,813,491														2,813,491	576,451	4,960,314
Term of warrants	5 years														5 years	5 years
Exercise price of warrants, per share	$ 0.55														$ 0.55	$ 0.825
Private Equity Offering | Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares																5,602,821
Term of warrants																5 years
Exercise price of warrants, per share																$ 1.00
Time Based Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, exercise price																$ 0.76
Vesting period																2 years
Stock options grant date fair value																$ 0.64
Stock options, term																10 years
Time Based Options | Executive Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares																550,000
Milestone Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares																450,000
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense															$ 1,300,000	$ 1,200,000	$ 2,400,000
Grant date fair value of options and warrants															1,400,000	$ 900,000	$ 1,700,000
Unrecognized compensation expense	$ 600,000														$ 600,000
Weighted average period over which unrecognized compensation expense is expected to be recognized															1 year 1 month 17 days
2012 Equity Incentive Plan | Director 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares																7,123
Stock options granted, exercise price																$ 0.61
Stock options grant date fair value																$ 0.36
Stock options, term																10 years
2012 Equity Incentive Plan | Employee Stock Option One | Managing Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares															450,000
Stock options granted, exercise price															$ 0.57
Stock options grant date fair value															$ 0.36
2012 Equity Incentive Plan | Employee Stock Option One | Managing Director | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															1 year
2012 Equity Incentive Plan | Employee Stock Option One | Managing Director | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															10 years
2012 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future stock-based grants	4,858,870														4,858,870
2012 Equity Incentive Plan | Stock Options | Before Amendment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance																			7,000,000			5,000,000	3,000,000
2012 Equity Incentive Plan | Stock Options | After Amendment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance																			15,000,000			7,000,000	5,000,000
2012 Equity Incentive Plan | Stock Options | Managing Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares																300,000
Stock options granted, exercise price																$ 1.09
Stock options grant date fair value																$ 0.78
2012 Equity Incentive Plan | Stock Options | Managing Director | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period																1 year
2012 Equity Incentive Plan | Stock Options | Managing Director | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period																10 years
2012 Equity Incentive Plan | Stock Options | Chief Science Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares															600,000
Stock options granted, exercise price															$ 0.57
Vesting period															3 years
Stock options grant date fair value															$ 0.35
Stock options, term															10 years
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares															800,000	1,050,000
Vesting period															3 years	3 years
Stock options grant date fair value															$ 0.35
Stock options, term															10 years	10 years
Stock options granted, exercise price, lower range limit															$ 0.57	$ 1.09
Stock options granted, exercise price, upper range limit																1.10
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options grant date fair value																0.75
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options grant date fair value																$ 0.76
2012 Equity Incentive Plan | Stock Options | Director 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares																100,000
Stock options granted, exercise price																$ 0.68
Stock options grant date fair value																$ 0.53
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage																25.00%
2012 Equity Incentive Plan | Stock Options | Director 2 | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, term																1 year
2012 Equity Incentive Plan | Stock Options | Director 2 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, term																10 years
2012 Equity Incentive Plan | Employee Stock Option Two | Managing Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares															836,055
Stock options granted, exercise price															$ 0.56
Vesting period															10 years
Stock options grant date fair value															$ 0.31
2012 Equity Incentive Plan | Stock Replacement Option | Executive Management and Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted, shares															1,050,000
Stock options granted, exercise price															$ 0.80
Vesting period															5 years
Stock options grant date fair value															$ 0.42
Stock options, term															10 years
Non-cash stock based compensation															$ 321,000
2012 Equity Incentive Plan | Warrants (equity allocation) | Consultant 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage															25.00%
Warrants granted, shares															200,000
Warrants granted, exercise price															$ 0.64
Warrants grant date fair value															$ 0.26
2012 Equity Incentive Plan | Warrants (equity allocation) | Consultant 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															5 years
Warrants granted, shares															100,000
Warrants granted, exercise price															$ 0.75
Warrants grant date fair value															$ 0.29
2012 Equity Incentive Plan | Warrants (equity allocation) | Consultant Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															5 years
Warrants granted, shares															50,000
Warrants granted, exercise price															$ 0.76
Warrants grant date fair value															$ 0.26
2012 Equity Incentive Plan | Warrants (equity allocation) | December 31, 2017 | Consultant 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage															25.00%
2012 Equity Incentive Plan | Warrants (equity allocation) | Milestone | Consultant 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage															50.00%
Offer to Amend and Exercise
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common shares, shares					51,090,113
Exercise price of warrants, per share					$ 0.50
Class of warrant or right expiration date	Dec. 22, 2017
Offer to Amend and Exercise | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share					$ 0.50
Expiration of tender offer					2018-10
Offer to Amend and Exercise | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share					$ 1.35
Expiration of tender offer					2022-10
Offer to Amend and Exercise | Subscription Agreements
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share					$ 0.50
Offer to Amend and Exercise | Private Equity Offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants, per share					$ 0.50