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Equity and Stock-based Compensation - Stock Plans - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2014 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Total intrinsic value of options exercised |  | $ 66,943 |  |
RSUs released and issued net of shares withheld for taxes |  | 526,055 |  |
Weighted-average fair value of awards granted |  | $ 29.99 | $ 54.74 | $ 53.69
2005 Stock Plan |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Vesting period of stock options |  | 4 years |  |
2005 Stock Plan | Maximum [Member] |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Expiration period of stock options |  | 10 years |  |
2014 Equity Incentive Plan |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Vesting period of stock options |  | 5 years |  |
Expiration period of stock options |  | 10 years |  |
Termination date of equity incentive plan |  | Nov. 12, 2024 |  |
Option vesting term |  | Option vesting schedules are determined by the Company at the time of issuance and generally have a four year vesting schedule (25% vesting on the first anniversary of the vesting base date and quarterly thereafter over the next 3 years). |  |
Number of common stock reserved for issuance |  | 7,909,854 |  |
Common stock reserved for future issuance, Description |  | Shares reserved for issuance increases on January 1 of each year commencing on January 1, 2016 and ending on January 1, 2024 by the lesser of (i) the amount equal to 4% of the number of shares issued and outstanding on December 31 immediately prior to the date of increase or (ii) such lower number of shares as may be determined by the board of directors. As of December 31, 2020, the Company has reserved 7,909,854 shares of its common stock that remains unissued for issuance under the 2014 Plan. |  |
Percentage of common stock reserved for future issuance | 4.00% |  |  |
Number of common stock repurchased |  | 0 | 0 |
Total intrinsic value of options exercised |  | $ 89,600 | $ 59,200 | $ 97,500
2014 Equity Incentive Plan | First Anniversary [Member] |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Percentage of vesting rights |  | 25.00% |  |
2014 Equity Incentive Plan | Maximum [Member] |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |
Percentage of fair value exercise price grant date |  | 100.00% |  |

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- Definition Description of service or performance condition required to be met for earning right to award under share-based payment arrangement. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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