Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended							12 Months Ended		1 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 2012 Performance Incentive Plan [Member]	Dec. 31, 2013 2012 Performance Incentive Plan [Member] Employee [Member]	Dec. 31, 2013 2012 Performance Incentive Plan [Member] Director [Member]	Dec. 31, 2013 Restricted Stock Units [Member]	Dec. 31, 2013 Employee Stock Purchase Plan [Member]	Dec. 31, 2013 2000 Non-Officer Equity Incentive Plan [Member]	Jan. 31, 2011 Common Shares [Member]	Dec. 31, 2013 Common Shares [Member]	Jan. 24, 2011 Common Shares [Member]	Jan. 28, 2014 Common Shares [Member] Subsequent Event [Member]	Jan. 31, 2014 Common Shares [Member] Subsequent Event [Member]	Dec. 31, 2013 Preferred Stock [Member]	Dec. 31, 2013 Series A Preferred Stock [Member]	Dec. 31, 2012 Series A Preferred Stock [Member]	Dec. 31, 2011 Series A Preferred Stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Preferred stock, shares authorized	10,000,000	10,000,000													10,000,000
Preferred stock, par value	$ 0.0001	$ 0.0001													$ 0.0001
Preferred stock, shares designated	0	0														0	0	3,100,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares issued	116,494,000	115,259,000										19,000,000	9,775,000
Proceeds from sale of common stock			$ 219,783,000							$ 220,400,000			$ 117,200,000	$ 117,200,000
Legal, accounting fees, filing fees and other offering expenses										600,000			600,000	600,000
Common stock, shares reserved for issuance in equity compensation plans											28,609,480
Additional new shares available for award grants				5,300,000
Service period for stock options granted					4 years	1 year
Number of common stock shares available for stock options grants				10,347,140
Share-based compensation plan's share limit reduction for every one restricted stock unit granted				1.5
Maximum term of stock options under equity incentive plans				8 years
Maximum term of stock options under equity incentive plans									8 years
Restricted Stock Units outstanding	0
RSU awards par value	$ 0.0001	$ 0.0001					$ 0.01
Restricted stock units award depletion ratio	1:1.5
Common stock, shares authorized	300,000,000	300,000,000						1,500,000
Percentage of purchase price of stock								85.00%
Maximum 401(k) per employee, percentage of annual salary	60.00%
Matching 401(k) employer contribution, maximum amount	3,000
Compensation expense in connection with 401(k) retirement plan	$ 1,000,000	$ 900,000	$ 900,000
Severance payment period for executives	12 months
Severance payment period for employees	6 months
Cash severance payment for chief executive officer	24 months base salary plus annual target incentive pay