Stockholders' Equity - Additional information (Detail)				1 Months Ended					12 Months Ended
	Dec. 16, 2015 shares	Jul. 02, 2015 USD ($)	Feb. 07, 2014 USD ($) $ / shares shares	Oct. 31, 2014 USD ($) shares	Sep. 30, 2014 USD ($) shares	Jan. 31, 2014 USD ($) shares	Nov. 30, 2013 USD ($)	Jul. 11, 2011 shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) Executives $ / shares shares	Dec. 31, 2014 USD ($) Executives $ / shares shares	Dec. 31, 2012 shares	Jul. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2016 shares	Dec. 31, 2013 shares	Dec. 03, 2012 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares issued									54,133,511	52,730,799
Proceeds from common stock | $									$ 2,460,000
Common Stock, par value | $ / shares									$ 0.001	$ 0.001
Company employees, directors and affiliates stock option exercised									147,425	235,480	1,332,563
Proceeds from common stock | $									$ 297,000	$ 755,000	$ 4,580,000
Preferred Stock, par value | $ / shares									$ 0.001	$ 0.001
Authorized shares of preferred stock									5,000,000	5,000,000
Number of RSUs vested									283,801
Common stock authorized beginning balance									75,000,000	75,000,000
Weighted average grant date fair value of options granted | $ / shares									$ 1.75	$ 4.99	$ 7.18
Number of options granted in period with exercise price below market price									0	0	0
Unrecognized compensation cost related to non-vested share-based compensation awards granted | $									$ 13,900,000
Unrecognized compensation cost related to non-vested share-based compensation awards granted year									4 years
Options outstanding									3,468,991	3,397,529	3,196,100				4,192,927
Warrants exercised to purchase shares of common stock											2,217,520
Warrants classified as derivative liabilities											1,999,153
Securities excluded from computation of diluted earnings per share									10,228,929	9,788,838	8,184,460
Number of executive officers from whom swing profits were recovered | Executives										1	3
Short swing profits recovered | $									$ 0	$ 6,000	$ 80,000
Dr. Andrew Finn [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares upon employee retirement	513,221
Issuance of common stock upon employee retirement														150,000
Employee retirement date									Dec. 31, 2015
Directors and Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period									653,373
RSU's Vested per performance criteria during period									3 years
Fair market value of shares granted | $									$ 1,100,000
Term of options granted period									10 years
Definitive Securities Purchase Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares issued			7,500,000
Proceeds from common stock | $			$ 58,200,000
Common Stock, par value | $ / shares			$ 0.001
Selling price of shares | $ / shares			$ 8.00
Offering price per share			3.10%
Employees and Directors Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company employees, directors and affiliates stock option exercised									100,000	200,000	1,300,000
Proceeds from common stock | $									$ 300,000	$ 800,000	$ 4,600,000
Warrant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding									84,986
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period									1,703,616
Fair market value of RSUs granted | $									$ 5,700,000
Vesting period of options									3 years
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants | $ / shares											$ 3.12
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants | $ / shares											$ 5.00
2011 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares of common stock authorized										2,250,000
2011 Equity Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized beginning balance										8,800,000
2011 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized beginning balance										11,050,000
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock options outstanding and exercisable								1,826,442
Term that options may be awarded								10 years
LTIP [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period									0	35,000
Restricted stock units ("RSUs") issued to directors and key employees									1,078,000			978,000
Restricted stock units reserved for future officers										100,000
RSU's Vested per performance criteria during period									8 years
Number of RSUs vested									13,347	21,356	4,447
Mid Cap Financial Trust [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock									84,986				357,356
Exercise price of warrants | $ / shares									$ 3.53				$ 4.20
Fair value of warrants | $									$ 50,000				$ 1,000,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's securities for shelf registration | $		$ 150,000,000					$ 75,000,000
Common Stock, shares issued				116,911	529,010	658,489
Proceeds from common stock | $				$ 1,900,000	$ 8,700,000	$ 3,900,000
Universal shelf registration amount, maximum | $		$ 40,000,000					$ 15,000,000
Company employees, directors and affiliates stock option exercised									147,426	223,923	1,332,563
Series A Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized shares of preferred stock									2,290,700
Series A Preferred shares issued									2,093,155							2,709,300
Liquidation, dissolution or winding up, holders of the Series A Preferred per share payment | $ / shares																$ 0.001
Series A Preferred stock converted									0	45,845	570,300