v2.4.0.6
Calculation of Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 6 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Sep. 30, 2012
Sep. 30, 2011
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2009
Numerator:              
Net income (loss) $ (6,684) $ 4,803 $ (27,417) $ 5,148 $ 9,830 $ (29,705) $ (5,906)
Accretion of redeemable convertible preferred stock (312) (320) (308) (471) (633) (640) (625)
Net income attributable to participating securities   (3,721)   (3,788) (7,558)    
Net income (loss) attributable to common stockholders - Basic (6,996) 762 (27,725) 889 1,639 (30,345) (6,531)
Undistributed earnings reallocated to participating securities   349   361 671    
Net income (loss) attributable to common stockholders - Diluted $ (6,996) $ 1,111 $ (27,725) $ 1,250 $ 2,310 $ (30,345) $ (6,531)
Denominator:              
Weighted-average shares outstanding - Basic 21,104,219 17,156,445 57,089,411 19,695,440 18,163,977 23,157,576 39,039,066
Effect of potentially dilutive securities:              
Common stock options   10,465,912   10,917,099 9,931,509    
Weighted-average shares outstanding - Diluted 21,104,219 27,622,357 57,089,411 30,612,539 28,095,486 23,157,576 39,039,066
Net income (loss) per share attributable to common stockholders:              
Basic $ (0.33) $ 0.04 $ (0.49) $ 0.05 $ 0.09 $ (1.31) $ (0.17)
Diluted $ (0.33) $ 0.04 $ (0.49) $ 0.04 $ 0.08 $ (1.31) $ (0.17)