Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 31, 2016	Dec. 31, 2013	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 12, 2016
Class of Stock [Line Items]
Number of warrants			623,605	623,605	1,176,105
Weighted Average Exercise Price			$ 2.50	$ 2.50	$ 3.67
Number of Warrants, Expired	552,500
Exercise price of expired warrants	$ 5.00
Remaining contractual life of warrants				7 months
Weighted-average fair value of market-based RSU, per share			$ 1.35	$ 1.35
Unrecognized compensation expense			$ 4,200,000	$ 4,200,000
Unrecognized compensation expense weighted average period				2 years 2 months 12 days
Market-based RSUs[Member]
Class of Stock [Line Items]
Expected dividends				0.00%
Restricted stock issued				700,000
At-the-Market Offering [Member]
Class of Stock [Line Items]
Common stock shares maximum aggregate offering price		$ 20,000,000
Stock issuances, sales agent commission maximum percentage		3.00%		3.00%
Common stock issued				0	0
President and CEO [Member]
Class of Stock [Line Items]
Options granted with annual vesting				850,000
Vesting period of granted options				4 years
Contractual life of option grants				10 years
Weighted-average grant date fair value, per share				$ 0.84
Exercise price of option				$ 3.63
Expected life of option				6 years 3 months
Stock volatility				70.00%
Risk-free interest rate				2.13%
Expected dividends				0.00%
President and CEO [Member] | Market-based RSUs[Member]
Class of Stock [Line Items]
Restricted stock issued				500,000
2016 Long Term Incentive Plan [Member]
Class of Stock [Line Items]
Number of new shares reserved for issuance			3,000,000	3,000,000
Number of previously authorized shares reserved for issuance from prior plans				489,241
Maximum potential number of previously outstanding shares equity awards from prior plan which could become available for grant as a result of future expirations or forfeitures			6,257,891	6,257,891
Shares available for grant			3,489,241	3,489,241
2008 Plan [Member]
Class of Stock [Line Items]
Shares available for grant						336,741
Options granted with annual vesting				1,535,300
Contractual life of option grants				10 years
Weighted-average grant date fair value, per share				$ 1.95
Options vested during the period				962,503
Exercise price of option				$ 2.14
Expected dividends				0.00%
2008 Plan [Member] | Market-based RSUs[Member]
Class of Stock [Line Items]
Restricted stock issued				200,000
2008 Plan [Member] | Employees [Member]
Class of Stock [Line Items]
Options granted with annual vesting				1,405,300
Vesting period of granted options				4 years
2008 Plan [Member] | Non-executive Directors [Member]
Class of Stock [Line Items]
Options granted with annual vesting				90,000
Vesting period of granted options				1 year
2008 Plan [Member] | Newly Appointed Non-executive Director [Member]
Class of Stock [Line Items]
Options granted with annual vesting				40,000
Vesting period of granted options				3 years
General and Administrative Expense [Member]
Class of Stock [Line Items]
Increase in stock-based compensation expense attributable to option modification to extend exercise period of vested stock options, net of non-vested option forfeitures				$ 274,000
Decrease in stock-based compensation expense attributable to stock option forfeitures, net of option modification to extend exercise period of vested stock options			$ 117,000	117,000
Research and Development Expense [Member] | U.K. [Member]
Class of Stock [Line Items]
Decrease in stock-based compensation expense attributable to stock option forfeitures, net of option modification to extend exercise period of vested stock options				$ 35,000