Stock Incentive Plans - Summary of Activity of Stock Incentive and Equity Plans (Detail)	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Shares available for grant
Shares available for grant, Beginning balance	732,270
Shares available for grant, Authorized	1,900,000
Shares available for grant, Granted	(640,470)
Shares available for grant, Exercised/Issued	0
Shares available for grant, Cancelled/forfeited	238,003
Shares available for grant, Ending balance	2,229,803
Number of options outstanding
Number of options outstanding, Beginning balance	2,851,568
Number of options outstanding, Authorized	0
Number of options outstanding, Granted	48,420
Number of options outstanding, Exercised/Issued	0
Number of options outstanding, Cancelled/forfeited	(189,559)
Number of options outstanding, Ending balance	2,710,429
Weighted - average option exercise price
Weighted - average option exercise price, Beginning balance | $ / shares	$ 7.07
Weighted - average option exercise price, Authorized | $ / shares	0
Weighted - average option exercise price, Granted | $ / shares	1.06
Weighted - average option exercise price, Exercised/Issued | $ / shares	0
Weighted - average option exercise price, Cancelled/forfeited | $ / shares	9.16
Weighted - average option exercise price, Ending balance | $ / shares	$ 6.81
Number of restricted stock and board shares issued
Number of restricted stock and board shares issued, Beginning balance	201,455
Number of restricted stock and board shares issued, Authorized	0
Number of restricted stock and board shares issued, Granted	592,050
Number of restricted stock and board shares issued, Exercised/Issued	0
Number of restricted stock and board shares issued, Cancelled/forfeited	0
Number of restricted stock and board shares issued, Ending balance	793,505
Restricted Stock Units [Member]
Number of restricted stock units outstanding
Number of restricted stock units outstanding, Beginning balance	454,021
Number of restricted stock units outstanding, Authorized	0
Number of restricted stock units outstanding, Granted	0
Number of restricted stock units outstanding, Exercised/Issued	(3,702)
Number of restricted stock units outstanding, Cancelled/forfeited	(58,491)
Number of restricted stock units outstanding, Ending balance	391,828