|
Stock Compensation Plans (Details 2) (USD $)
|
9 Months Ended |
|
Oct. 31, 2012
|
| Shares |
|
| Options granted (in shares) |
3,549,276 |
| Options forfeited (in shares) |
(955,819) |
| Number of Shares |
|
| RSUs granted (in shares) |
401,724 |
| RSUs forfeited (in shares) |
(2,500) |
|
ESPP
|
|
| Employee Stock Purchase Plan |
|
| Maximum percentage of eligible compensation that can be used to purchase shares of common stock |
15.00% |
| Purchase price of shares as a percentage of fair value of common stock |
85.00% |
| Offering period |
12 months |
|
Options
|
|
| Shares |
|
| Outstanding at the beginning of the period (in shares) |
21,905,290 |
| Options granted (in shares) |
3,549,276 |
| Options exercised (in shares) |
(2,308,582) |
| Options forfeited (in shares) |
(955,819) |
| Outstanding at the end of the period (in shares) |
22,190,165 |
| Vested and expected to vest at the end of the period (in shares) |
20,904,544 |
| Vested and exercisable at the end of the period (in shares) |
10,281,417 |
| Weighted-Average Exercise Price Per Share |
|
| Balances at the beginning of the period (in dollars per share) |
1.92 |
| Options granted (in dollars per share) |
13.24 |
| Options exercised (in dollars per share) |
0.92 |
| Options forfeited (in dollars per share) |
3.23 |
| Balances at the end of the period (in dollars per share) |
3.77 |
| Vested and expected to vest at the end of the period (in dollars per share) |
3.65 |
| Vested and exercisable at the end of the period (in dollars per share) |
1.06 |
| Weighted-Average Remaining Contractual Term |
|
| Balances at the end of the period |
7 years 9 months 22 days |
| Vested and expected to vest at the end of the period |
7 years 9 months |
| Vested and exercisable at the end of the period |
6 years 7 months 13 days |
| Aggregate Intrinsic Value |
|
| Outstanding at the end of the period (in dollars) |
542,345,000 |
| Vested and expected to vest at the end of the period (in dollars) |
513,409,000 |
| Vested and exercisable at the end of the period (in dollars) |
277,245,000 |
| Unrecognized compensation cost |
|
| Total unrecognized compensation cost related to stock options |
32,700,000 |
| Weighted-average period over which unrecognized compensation cost is expected to be recognized |
3 years 2 months 12 days |
| Additional disclosures |
|
| Total intrinsic value of options exercised (in dollars) |
46,800,000 |
| Weighted-average grant date fair value of options granted (in dollars per share) |
7.52 |
|
RSUs
|
|
| Unrecognized compensation cost |
|
| Total unrecognized compensation cost |
11,500,000 |
| Weighted-average period over which unrecognized compensation cost is expected to be recognized |
3 years 8 months 26 days |
| Additional disclosures |
|
| Weighted-average grant date fair value of RSUs granted (in dollars per share) |
34.60 |
| Number of Shares |
|
| RSUs granted (in shares) |
401,724 |
| RSUs forfeited (in shares) |
(2,500) |
| Balances at the end of the period (in shares) |
399,224 |
| RSU's vested and expected to vest at the end of the period (in shares) |
356,242 |