XML 134 R40.htm IDEA: XBRL DOCUMENT
v3.20.4

Stock-Based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Share-based Payment Arrangement [Abstract] |
Options Activity | The following table summarizes our option activity as of December 31, 2020 and 2019:
|  | Number of Options |  | Weighted Average Exercise Price per Share |  | Weighted Average Grant Date Fair Value per Share |  | Weighted- Average Remaining Contractual Term |  | Aggregate Intrinsic Value (1) (in thousands)
Outstanding at December 31, 2019 |  | 45,536,915 |  |  | $ | 13.82 |  |  | $ | 7.35 |  |  | 7.2 years |  | $ | 286,310 |
Granted |  | 5,036,520 |  |  | 36.04 |  |  | 19.30 |  |  |  |  |
Exercised |  | (13,888,434) |  |  | 12.93 |  |  | 6.68 |  |  |  |  |
Canceled/forfeited |  | (2,627,468) |  |  | 18.14 |  |  | 10.56 |  |  |  |  |
Outstanding at December 31, 2020 |  | 34,057,533 |  |  | 17.14 |  |  | 9.12 |  |  | 6.7 years |  | 2,976,235 |
Exercisable at December 31, 2020 |  | 17,461,374 |  |  | 10.99 |  |  | 5.67 |  |  | 5.4 years |  | 1,632,365 |
Expected to vest at December 31, 2020 |  | 16,596,159 |  |  | 23.61 |  |  | 12.75 |  |  | 8.2 years |  | 1,343,870 |
_______ (1)Aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of common stock for those options in the money as of December 31, 2020.
Restricted Common Stock Units Activity | The following table summarizes our restricted stock unit activity during the year ended December 31, 2020:
| Number of Units |  | Weighted Average Grant Date Price per Unit
Outstanding, non-vested at December 31, 2019 | 1,177,249 |  |  | $ | 19.01 |
Issued | 1,478,093 |  |  | 37.37 |
Vested | (247,349) |  |  | 20.28 |
Canceled/forfeited | (215,033) |  |  | 23.64 |
Outstanding, non-vested at December 31, 2020 | 2,192,960 |  |  | 30.85 |
Weighted-Average Assumptions Used to Estimate the Fair Value of Options Granted | The weighted-average assumptions used to estimate the fair value of options granted and ESPP for the years ended December 31, 2020, 2019 and 2018 are as follows:
|  | Weighted Average
|  | Years Ended December 31,
|  | 2020 |  | 2019 |  | 2018
Options: |  |  |  |  |  |
Risk-free interest rate |  | 0.83 | % |  | 2.29 | % |  | 2.76 | %
Expected term |  | 6.11 years |  | 6.07 years |  | 6.27 years
Expected volatility |  | 58 | % |  | 61 | % |  | 63 | %
Expected dividends |  | — | % |  | — | % |  | — | %
Weighted average fair value per share |  | $ | 19.30 |  |  | $ | 11.35 |  |  | $ | 9.33 |
ESPP: |  |  |  |  |  |
Risk-free interest rate |  | 0.14 | % |  | 1.95 | % |  | *
Expected term |  | 0.50 years |  | 0.50 years |  | *
Expected volatility |  | 54 | % |  | 53 | % |  | *
Expected dividends |  | — | % |  | — | % |  | *
Weighted average fair value per share |  | $ | 32.18 |  |  | $ | 5.98 |  |  | *
_________ * - Not applicable
Stock-Based Compensation Expense | The following table presents the components and classification of stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 as follows (in thousands):
| Years Ended December 31,
| 2020 |  | 2019 |  | 2018
Options | $ | 77,748 |  |  | $ | 74,780 |  |  | $ | 63,288 |
Restricted common stock and units | 12,401 |  |  | 5,125 |  |  | 9,277 |
Employee stock purchase plan | 2,872 |  |  | 1,217 |  |  | — |
Total | $ | 93,021 |  |  | $ | 81,122 |  |  | $ | 72,565 |
Research and development | $ | 56,155 |  |  | $ | 48,259 |  |  | $ | 37,659 |
Selling, general and administrative | 36,866 |  |  | 32,863 |  |  | 34,906 |
Total | $ | 93,021 |  |  | $ | 81,122 |  |  | $ | 72,565 |

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of allocation of amount expensed and capitalized for award under share-based payment arrangement to statement of income or comprehensive income and statement of financial position. Includes, but is not limited to, corresponding line item in financial statement. + 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 (h)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901 + Details
Name: | us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in outstanding nonvested restricted stock units. + 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 (c)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + 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 (f)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of number, weighted-average exercise price or conversion ratio, aggregate intrinsic value, and weighted-average remaining contractual term for outstanding and exercisable options that are fully vested and expected to vest. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. + 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 (e) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAndExercisableTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration