v2.4.0.6
Quarterly Financial Information (Schedule Of Quarterly Financial Information) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Quarterly Financial Information [Abstract]                      
Revenues $ 62,586 $ 58,759 $ 58,095 $ 52,952 $ 51,195 $ 45,703 $ 41,962 $ 36,139 $ 232,392 $ 174,999 $ 127,740
Cost of revenues 19,102 [1] 19,560 [1] 19,302 [1] 17,139 [1] 15,477 [1] 13,743 [1] 12,374 [1] 10,359 [1] 75,103 [2] 51,953 [2] 38,730 [2]
Selling and marketing 20,073 [1] 20,330 [1] 19,717 [1] 18,169 [1] 17,712 [1] 16,319 [1] 12,892 [1] 12,718 [1] 78,289 [2] 59,641 [2] 41,954 [2]
Research and development 8,099 [1] 9,219 [1] 8,833 [1] 7,899 [1] 7,988 [1] 7,254 [1] 6,088 [1] 5,047 [1] 34,050 [2] 26,377 [2] 17,827 [2]
General and administrative 11,651 [1] 12,568 [1] 13,977 [1] 10,318 [1] 9,376 [1] 10,204 [1] 8,167 [1] 6,206 [1] 48,514 [2] 33,953 [2] 18,232 [2]
Amortization 2,415 2,458 2,434 1,994 1,989 1,380 658 507 9,301 4,534 1,457
Settlement of litigation 5,175               5,175    
Total expenses from operations 66,515 64,135 64,263 55,519 52,542 48,900 40,179 34,837 250,432 176,458 118,200
(Loss) from operations (3,929) (5,376) (6,168) (2,567) (1,347) (3,197) 1,783 1,302 (18,040) (1,459) 9,540
Interest and other (expense) income, net (169) (143) (124) (89) (64) (37) 40 114 (525) 53 410
Gain (loss) from foreign currency (320) (342) 102 150 (135) (83) (12) (117) (410) (347) (132)
Gain on sale of marketable securities   211             211   89
(Loss) before income taxes (4,418) (5,650) (6,190) (2,506) (1,546) (3,317) 1,811 1,299 (18,764) (1,753) 9,907
Benefit (provision) for income taxes 1,129 1,712 (2,039) 2,172 1,051 1,182 (986) (1,070) 2,974 177 (5,938)
Net (loss) income (3,289) (3,938) (8,229) (334) (495) (2,135) 825 229 (15,790) (1,576) 3,969
Net (loss) available to common stockholders per common share:                          
Basic $ (0.10) $ (0.12) $ (0.26) $ (0.01) $ (0.02) $ (0.07) $ 0.03 $ 0.01 $ (0.49) $ (0.05) $ 0.13
Diluted $ (0.10) $ (0.12) $ (0.26) $ (0.01) $ (0.02) $ (0.07) $ 0.03 $ 0.01 $ (0.49) $ (0.05) $ 0.13
Weighted-average number of shares used in per share calculations                      
Basic 33,159,350 32,492,939 31,832,105 31,656,904 31,449,665 31,223,077 30,965,800 30,630,461 32,289,877 31,070,018 30,014,085
Diluted 33,159,350 32,492,939 31,832,105 31,656,904 31,449,665 31,223,077 31,736,718 31,475,136 32,289,877 31,070,018 30,970,642
[1] (1) Amortization of stock-based compensation is included in the line items above as follows
[2] (1) Amortization of stock-based compensation is included in the line items above as follows Cost of revenues $ 1,976 $ 1,494 $ 1,186 Selling and marketing 8,512 6,217 4,617 Research and development 1,988 1,868 1,111 General and administrative 8,784 8,195 2,942 General and administrative 8,784 8,195 2,942