XML 47 R28.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stock-based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 28, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Schedule of Allocated Employee Stock-Based Compensation Expense | We allocated the stock-based compensation expense for our equity incentive plans and our 2000 Employee Stock Purchase Plan (ESPP) as follows (in thousands):
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
Research and development | $ | 13,115 |  |  | $ | 7,569 |  |  | $ | 9,366 |
Selling, general and administrative | 27,511 |  |  | 16,369 |  |  | 13,546 |
Total stock-based compensation | $ | 40,626 |  |  | $ | 23,938 |  |  | $ | 22,912 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | The weighted average grant-date fair value per share of stock options and ESPP purchases was as follows:
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
Stock options | $ | 9.07 |  |  | $ | 11.42 |  |  | $ | 4.77 |
ESPP | $ | 6.40 |  |  | $ | 6.00 |  |  | $ | 2.17 |
Schedule of Fair Value of Employee Share-Based Payments Awards Stock Option Assumptions and Weighted Average Fair Values | The grant-date fair value of stock option grants and ESPP purchases was estimated using the following assumptions:
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
Stock options: |  |  |  |  |
Risk-free interest rate | 2.81 | % |  | 1.98 | % |  | 1.15 | %
Dividend yield | — | % |  | — | % |  | — | %
Volatility | 55 | % |  | 59 | % |  | 76 | %
Expected life | 4.4 years |  |  | 4.5 years |  |  | 4.4 years |
ESPP: |  |  |  |  |
Risk-free interest rate | 1.93 | % |  | 1.09 | % |  | 0.55 | %
Dividend yield | — | % |  | — | % |  | — | %
Volatility | 53 | % |  | 58 | % |  | 65 | %
Expected life | 6 months |  |  | 6 months |  |  | 6 months |
Schedule of Fair Value of Employee Share-Based Payments Awards ESPP Assumptions and Weighted Average Fair Values | The grant-date fair value of stock option grants and ESPP purchases was estimated using the following assumptions:
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
Stock options: |  |  |  |  |
Risk-free interest rate | 2.81 | % |  | 1.98 | % |  | 1.15 | %
Dividend yield | — | % |  | — | % |  | — | %
Volatility | 55 | % |  | 59 | % |  | 76 | %
Expected life | 4.4 years |  |  | 4.5 years |  |  | 4.4 years |
ESPP: |  |  |  |  |
Risk-free interest rate | 1.93 | % |  | 1.09 | % |  | 0.55 | %
Dividend yield | — | % |  | — | % |  | — | %
Volatility | 53 | % |  | 58 | % |  | 65 | %
Expected life | 6 months |  |  | 6 months |  |  | 6 months |
Summary of All Stock Option Activity | Activity for stock options during the year ended December 31, 2018 was as follows (dollars in thousands, except per share amounts):
| Shares |  | Weighted Average Exercise Price |  | Weighted Average Remaining Contractual Term |  | Aggregate Intrinsic Value
Stock options outstanding at December 31, 2017 | 22,208,446 |  |  | $ | 6.83 |  |  |  |  |
Granted | 3,238,473 |  |  | $ | 19.40 |  |  |  |  |
Exercised | (2,466,579 | ) |  | $ | 4.90 |  |  |  |  |
Forfeited | (288,197 | ) |  | $ | 15.71 |  |  |  |  |
Expired | (18,081 | ) |  | $ | 20.64 |  |  |  |  |
Stock options outstanding at December 31, 2018 | 22,674,062 |  |  | $ | 8.71 |  |  | 3.7 years |  | $ | 254,201 |
Exercisable at December 31, 2018 | 16,463,202 |  |  | $ | 5.65 |  |  | 3.0 years |  | $ | 229,699 |
Summary of All RSU Activity | Activity for RSUs during the year ended December 31, 2018 was as follows (dollars in thousands, except per share amounts):
| Shares |  | Weighted Average Grant Date Fair Value |  | Weighted Average Remaining Contractual Term |  | Aggregate Intrinsic Value
RSUs outstanding at December 31, 2017 | 3,762,990 |  |  | $ | 17.76 |  |  |  |  |
Awarded | 2,519,425 |  |  | $ | 18.46 |  |  |  |  |
Vested and released | (1,081,339 | ) |  | $ | 16.05 |  |  |  |  |
Forfeited | (343,742 | ) |  | $ | 18.99 |  |  |  |  |
RSUs outstanding at December 31, 2018 | 4,857,334 |  |  | $ | 18.42 |  |  | 2.1 years |  | $ | 94,427 |

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 the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed. + 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=109197908&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=109197908&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=109197908&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 for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + 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 (d) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 Reference 2: 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=109197908&loc=d3e5070-113901 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
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 employee stock purchase plans, including, but not limited to: (a) expected term, (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=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock
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=109197908&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 the weighted-average grant-date fair value of equity options or other equity instruments granted during the year. + 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 (d)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValueTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration