Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended															12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	Dec. 31, 2013 Restricted stock [Member]	Dec. 31, 2012 Restricted stock [Member]	Dec. 31, 2011 Restricted stock [Member]	Dec. 31, 2013 Restricted stock [Member] Board of Directors non-employee [Member]	Dec. 31, 2013 Restricted stock [Member] Key officers and employees [Member]	Dec. 31, 2013 Stock options [Member]	Dec. 31, 2013 1995 Stock Option Plan [Member]	Dec. 31, 2013 2005 Stock Option [Member]	Dec. 31, 2013 2005 Stock Option [Member] Maximum [Member]	Oct. 11, 2007 2005 Stock Option [Member] Minimum [Member]	Jul. 28, 2005 2005 Stock Option [Member] Minimum [Member]	Dec. 31, 2013 2005 Stock Option [Member] Restricted stock [Member] Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
1995 Stock option expiry date											May 24, 2005
Restricted stock vesting period								12 months	48 months			4 years	48 months			12 months
Stock option expiration period												10 years
Maximum number of shares available for issuance under plan				1,000,000										7,000,000	5,000,000
Additional shares authorized, percent												2.50%
Number of additional shares authorized												750,000
Percentage of market value				85.00%
Percentage of employee's payroll deductions limited to employee's compensation				10.00%
Maximum Stock value of shares purchased by employees if one thousand shares purchased				$ 25,000
Maximum number of shares that employee can purchase each period				1,000
Restricted stock shares granted								40,000	1,500,000
Value of restricted stock granted								100,000	2,500,000
Stock-based compensation	3,533,000	3,949,000	6,530,000		400,000	400,000	1,500,000
Exercise of common stock options, shares		32,000	7,000							0
Weighted average grant-date fair value of stock options granted	$ 0.63	$ 0.80	$ 1.16
Unrecognized compensation costs related to non-vested awards granted										$ 4,300,000
Number of shares available for future grants												2,000,000