Stock-Based Compensation - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Apr. 25, 2013	Dec. 31, 2014	Dec. 31, 2013	Feb. 11, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiry period of option plan		10 years
Compensation expense recognized for stock option		$ 413,000	$ 1,301,000
Cash received from options and warrants exercised			18,000
Number of stock options to purchase		1,308,835
Common stock at exercise prices range, minimum		$ 1.31
Common stock at exercise prices range, maximum		$ 68.90
Total options outstanding		101,376	126,183
Weighted Average Exercise Price per Share Vested and exercisable		$ 13.45	$ 25.60
Weighted average fair value of options granted		$ 1.22	$ 6.00
Total intrinsic value of options exercised		0	17,000
Requisite service periods for options granted for employees		4 years	4 years
Requisite service periods for options granted to directors		1 year	1 year
Total options outstanding		1,308,835	306,616		242,654
Options nonvested		1,207,459
Total unrecognized compensation cost related to unvested options		1,293,000
Total unrecognized compensation cost to be recognized over the requisite service period		901,000
Fully vested options				90,000
Fully vested options lapsed	90,000
Fully vested options lapsing exercise restriction date		Apr. 25, 2013
Additional stock compensation recognized	423,000
2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	3,500,000
2005 and 2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares of common stock available for grant		2,301,691
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested upon the attainment of milestone		392,425
Total unrecognized compensation cost		$ 392,000