XML 64 R43.htm IDEA: XBRL DOCUMENT
v3.20.4

Equity Incentive Plans and Stock-Based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Share-based Payment Arrangement [Abstract] |
Schedule of shares available for grant | A summary of shares available for grant under the Company’s plans is as follows:
| Shares Available for Grant
Total shares available for grant as of December 31, 2017 | 5,051,147
Increase in shares approved for issuance | 5,500,000
Stock options granted | (711,479)
Stock options forfeited | 877,803
Nonvested equity stock and stock units granted (1) (2) | (4,993,802)
Nonvested equity stock and stock units forfeited (1) | 4,350,377
Total shares available for grant as of December 31, 2018 | 10,074,046
Increase in shares approved for issuance (3) | 400,000
Stock options granted | (80,000)
Stock options forfeited | 426,960
Nonvested equity stock and stock units granted (1) (4) | (7,261,845)
Nonvested equity stock and stock units forfeited (1) | 3,267,702
Total shares available for grant as of December 31, 2019 | 6,826,863
Increase in shares approved for issuance (5) | 7,800,000
Stock options granted | (40,000)
Stock options forfeited | 101,816
Nonvested equity stock and stock units granted (1) (6) | (3,528,401)
Nonvested equity stock and stock units forfeited (1) | 1,252,042
Total shares available for grant as of December 31, 2020 | 12,412,320
______________________________________ (1) For purposes of determining the number of shares available for grant under the 2015 Plan against the maximum number of shares authorized, each restricted stock granted reduces the number of shares available for grant by 1.5 shares and each restricted stock forfeited increases shares available for grant by 1.5 shares. (2) Amount includes 0.5 million shares that had been reserved for potential future issuance related to certain performance unit awards discussed under the section titled “Nonvested Equity Stock and Stock Units” below. (3) Shares were reserved under the 2019 Inducement Plan adopted in the third quarter of 2019. (4) Amount includes 1.0 million shares that have been reserved for potential future issuance related to certain performance unit awards discussed under the section titled “Nonvested Equity Stock and Stock Units” below. (5) On April 30, 2020, the Company’s stockholders approved an additional 7,800,000 shares for issuance under the 2015 Plan. (6) Amount includes 0.5 million shares that have been reserved for potential future issuance related to certain performance unit awards discussed under the section titled “Nonvested Equity Stock and Stock Units” below.
Schedule of stock option activity | The following table summarizes stock option activity under the Company’s equity incentive plans for the years ended December 31, 2020, 2019 and 2018 and information regarding stock options outstanding, exercisable, and vested and expected to vest as of December 31, 2020:
|  | Options Outstanding |  | Weighted-Average Remaining Contractual Term |  |
(In thousands, except per share amounts and years) |  | Number of Shares |  | Weighted-Average Exercise Price per Share |  |  | Aggregate Intrinsic Value
Outstanding as of December 31, 2017 |  | 4,310,361 |  | $ | 9.78 |  |  |  |  |
Options granted |  | 711,479 |  | $ | 12.84 |  |  |  |  |
Options exercised |  | (908,146) |  | $ | 6.70 |  |  |  |  |
Options forfeited |  | (877,803) |  | $ | 13.73 |  |  |  |  |
Outstanding as of December 31, 2018 |  | 3,235,891 |  | $ | 10.25 |  |  |  |  |
Options granted |  | 80,000 |  | $ | 13.25 |  |  |  |  |
Options exercised |  | (1,249,785) |  | $ | 7.79 |  |  |  |  |
Options forfeited |  | (426,960) |  | $ | 13.71 |  |  |  |  |
Outstanding as of December 31, 2019 |  | 1,639,146 |  | $ | 11.37 |  |  |  |  |
Options granted |  | 40,000 |  | $ | 15.59 |  |  |  |  |
Options exercised |  | (613,119) |  | $ | 10.74 |  |  |  |  |
Options forfeited |  | (101,816) |  | $ | 19.41 |  |  |  |  |
Outstanding as of December 31, 2020 |  | 964,211 |  | $ | 11.08 |  |  | 5.04 |  | $ | 6,151 |
Vested or expected to vest at December 31, 2020 |  | 961,925 |  | $ | 11.08 |  |  | 5.03 |  | $ | 6,143 |
Options exercisable at December 31, 2020 |  | 781,102 |  | $ | 10.51 |  |  | 4.31 |  | $ | 5,432 |
Weighted-average assumptions for stock option plan | The following table presents the weighted-average assumptions used to estimate the fair value of stock options granted that contain only service conditions in the periods presented:
| Stock Option Plan for Years Ended December 31,
| 2020 |  | 2019 |  | 2018
Stock Option Plan |  |  |  |  |
Expected stock price volatility | 38% |  | 33%-36% |  | 24%-32%
Risk free interest rate | 0.2% |  | 1.4%-1.6% |  | 2.6%-2.8%
Expected term (in years) | 5.5 |  | 5.1-5.2 |  | 5.8
Weighted-average fair value of stock options granted | $5.46 |  | $4.36 |  | $4.23
Weighted-average assumptions for employee stock purchase plan |
| Employee Stock Purchase Plan for Years Ended December 31,
| 2020 |  | 2019 |  | 2018
Employee Stock Purchase Plan |  |  |  |  |
Expected stock price volatility | 37%-46% |  | 32% |  | 27%-34%
Risk free interest rate | 0.1% |  | 1.6%-2.4% |  | 2.05%-2.5%
Expected term (in years) | 0.5 |  | 0.5 |  | 0.5
Weighted-average fair value of purchase rights granted under the purchase plan | $3.46 |  | $3.13 |  | $2.59
Schedule of nonvested equity stock and stock units activity | The following table reflects the activity related to nonvested equity stock and stock units for the three years ended December 31, 2020:
Nonvested Equity Stock and Stock Units | Shares |  | Weighted-Average Grant-Date Fair Value
Nonvested at December 31, 2017 | 5,861,349 |  | $ | 12.68 |
Granted | 2,978,558 |  | $ | 12.77 |
Vested | (1,713,930) |  | $ | 12.39 |
Forfeited | (2,266,842) |  | $ | 12.97 |
Nonvested at December 31, 2018 | 4,859,135 |  | $ | 12.71 |
Granted | 4,233,701 |  | $ | 10.17 |
Vested | (1,896,283) |  | $ | 12.40 |
Forfeited | (1,907,070) |  | $ | 11.33 |
Nonvested at December 31, 2019 | 5,289,483 |  | $ | 11.27 |
Granted | 1,986,117 |  | $ | 15.60 |
Vested | (1,693,659) |  | $ | 11.70 |
Forfeited | (730,676) |  | $ | 11.83 |
Nonvested at December 31, 2020 | 4,851,265 |  | $ | 12.82 |

X
- Definition Tabular disclosure of the number of shares available for grant under the company plan that were outstanding at the beginning and end of the year. + References No definition available. + Details
Name: | rmbs_ScheduleOfShareBasedCompensationStockOptionsAwardsNumberOfSharesActivityTableTextBlock
Namespace Prefix: | rmbs_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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 changes in outstanding nonvested shares. + 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_ScheduleOfNonvestedShareActivityTableTextBlock
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=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 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=120381028&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=120381028&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=120381028&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=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration