Equity Incentive Plans - Schedule of Stock Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number	21,372,960	22,640,942
Options Outstanding, Weighted Average Exercise Price	$ 35.93	$ 26.70
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	5 years 5 months 23 days	6 years 4 months 13 days
Options Exercisable, Number	11,957,510	10,714,106
Options Exercisable, Weighted Average Exercise Price	$ 12.37	$ 12.37
Options Exercisable, Weighted Average Remaining Contractual Life (in years)	3 years 7 months 17 days	4 years 4 days
$2.70 - $6.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 2.70
Range of Exercise Price, Upper limit	$ 6.15
Options Outstanding, Number	329,072
Options Outstanding, Weighted Average Exercise Price	$ 3.13
Options Exercisable, Number	327,696
Options Exercisable, Weighted Average Exercise Price	$ 3.13
$6.63 - $6.63 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 6.63	$ 6.63
Range of Exercise Price, Upper limit	$ 6.63	$ 6.63
Options Outstanding, Number	7,030,489	7,096,725
Options Outstanding, Weighted Average Exercise Price	$ 6.63	$ 6.63
Options Exercisable, Number	7,029,293	7,093,020
Options Exercisable, Weighted Average Exercise Price	$ 6.63	$ 6.63
$9.96 - $28.45 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 9.96
Range of Exercise Price, Upper limit	$ 28.45
Options Outstanding, Number	2,183,386
Options Outstanding, Weighted Average Exercise Price	$ 23.87
Options Exercisable, Number	1,779,133
Options Exercisable, Weighted Average Exercise Price	$ 23.19
$29.12 - $31.07 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 29.12
Range of Exercise Price, Upper limit	$ 31.07
Options Outstanding, Number	1,105,021
Options Outstanding, Weighted Average Exercise Price	$ 30.00
Options Exercisable, Number	606,484
Options Exercisable, Weighted Average Exercise Price	$ 30.00
$31.17 - $31.17 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 31.17
Range of Exercise Price, Upper limit	$ 31.17
Options Outstanding, Number	5,611,130
Options Outstanding, Weighted Average Exercise Price	$ 31.17
Options Exercisable, Number	663,860
Options Exercisable, Weighted Average Exercise Price	$ 31.17
$31.49 - $38.42 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 31.49
Range of Exercise Price, Upper limit	$ 38.42
Options Outstanding, Number	2,376,417
Options Outstanding, Weighted Average Exercise Price	$ 33.25
Options Exercisable, Number	1,167,109
Options Exercisable, Weighted Average Exercise Price	$ 32.82
$39.10 - $179.72 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 39.10
Range of Exercise Price, Upper limit	$ 179.72
Options Outstanding, Number	2,140,496
Options Outstanding, Weighted Average Exercise Price	$ 111.51
Options Exercisable, Number	379,519
Options Exercisable, Weighted Average Exercise Price	$ 94.50
$184.67 - $259.32 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 184.67
Range of Exercise Price, Upper limit	$ 259.32
Options Outstanding, Number	498,658
Options Outstanding, Weighted Average Exercise Price	$ 233.06
Options Exercisable, Number	84
Options Exercisable, Weighted Average Exercise Price	$ 198.09
$259.94 - $259.94 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 259.94
Range of Exercise Price, Upper limit	$ 259.94
Options Outstanding, Number	72,333
Options Outstanding, Weighted Average Exercise Price	$ 259.94
Options Exercisable, Number	4,332
Options Exercisable, Weighted Average Exercise Price	$ 259.94
$282.11 - $282.11 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit	$ 282.11
Range of Exercise Price, Upper limit	$ 282.11
Options Outstanding, Number	25,958
Options Outstanding, Weighted Average Exercise Price	$ 282.11
$0.15 - $6.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 0.15
Range of Exercise Price, Upper limit		$ 6.15
Options Outstanding, Number		523,182
Options Outstanding, Weighted Average Exercise Price		$ 3.16
Options Exercisable, Number		516,728
Options Exercisable, Weighted Average Exercise Price		$ 3.16
$9.96 - $28.35 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 9.96
Range of Exercise Price, Upper limit		$ 28.35
Options Outstanding, Number		2,266,058
Options Outstanding, Weighted Average Exercise Price		$ 22.08
Options Exercisable, Number		1,302,499
Options Exercisable, Weighted Average Exercise Price		$ 19.70
$28.43 - $31.07 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 28.43
Range of Exercise Price, Upper limit		$ 31.07
Options Outstanding, Number		2,136,721
Options Outstanding, Weighted Average Exercise Price		$ 29.48
Options Exercisable, Number		864,050
Options Exercisable, Weighted Average Exercise Price		$ 29.24
$31.07 - $31.07 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 31.07
Range of Exercise Price, Upper limit		$ 31.07
Options Outstanding, Number		5,715,734
Options Outstanding, Weighted Average Exercise Price		$ 31.17
Options Exercisable, Number		91,541
Options Exercisable, Weighted Average Exercise Price		$ 31.17
$31.49 - $34.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 31.49
Range of Exercise Price, Upper limit		$ 34.00
Options Outstanding, Number		2,288,998
Options Outstanding, Weighted Average Exercise Price		$ 32.07
Options Exercisable, Number		707,052
Options Exercisable, Weighted Average Exercise Price		$ 31.98
$34.57 - $141.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 34.57
Range of Exercise Price, Upper limit		$ 141.60
Options Outstanding, Number		2,266,350
Options Outstanding, Weighted Average Exercise Price		$ 60.57
Options Exercisable, Number		127,674
Options Exercisable, Weighted Average Exercise Price		$ 45.62
$144.70 - $147.38 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 144.70
Range of Exercise Price, Upper limit		$ 147.38
Options Outstanding, Number		252,945
Options Outstanding, Weighted Average Exercise Price		$ 147.31
Options Exercisable, Number		11,542
Options Exercisable, Weighted Average Exercise Price		$ 147.38
$160.70 - $160.70 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 166.70
Range of Exercise Price, Upper limit		$ 160.70
Options Outstanding, Number		18,975
Options Outstanding, Weighted Average Exercise Price		$ 160.70
$179.72 - $179.72 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower limit		$ 179.72
Range of Exercise Price, Upper limit		$ 179.72
Options Outstanding, Number		75,254
Options Outstanding, Weighted Average Exercise Price		$ 179.72