XML 55 R39.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Equity Incentive Plans and Stock-Based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Shares available for grant under stock-based incentive plans | A summary of shares available for grant under the Company’s plans is as follows:
| Shares Available for Grant
Shares available as of December 31, 2012 | 2,729,159
Stock options granted | (2,084,276)
Stock options forfeited | 3,318,022
Stock options expired under former plans | (1,157,419)
Nonvested equity stock and stock units granted (1) | (709,611)
Nonvested equity stock and stock units forfeited (1) | 431,553
Total shares available for grant as of December 31, 2013 | 2,527,428
Increase in shares approved for issuance | 10,000,000
Stock options granted | (2,370,313)
Stock options forfeited | 1,400,349
Stock options expired under former plans | (373,043)
Nonvested equity stock and stock units granted (1) | (585,753)
Nonvested equity stock and stock units forfeited (1) | 125,560
Total shares available for grant as of December 31, 2014 | 10,724,228
Increase in shares approved for issuance | 4,000,000
Stock options granted | (362,335)
Stock options forfeited | 1,624,823
Stock options expired under former plans | (657,878)
Nonvested equity stock and stock units granted (1) (2) | (4,537,797)
Nonvested equity stock and stock units forfeited (1) | 382,504
Total shares available for grant as of December 31, 2015 | 11,173,545
______________________________________
(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 238,980 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 stock option plans for the years ended December 31, 2015, 2014 and 2013 and information regarding stock options outstanding, exercisable, and vested and expected to vest as of December 31, 2015.
| Options Outstanding |  | Weighted Average Remaining Contractual Term |  |
| Number of Shares |  | Weighted Average Exercise Price per Share |  |  | Aggregate Intrinsic Value
| (Dollars in thousands, except per share amounts)
Outstanding as of December 31, 2012 | 13,094,815 |  | $ | 12.79 |  |  |  |  |
Options granted | 2,084,276 |  | $ | 6.09 |  |  |  |  |
Options exercised | (483,923) |  | $ | 6.72 |  |  |  |  |
Options forfeited | (3,318,022) |  | $ | 14.51 |  |  |  |  |
Outstanding as of December 31, 2013 | 11,377,146 |  | $ | 11.32 |  |  |  |  |
Options granted | 2,370,313 |  | $ | 9.63 |  |  |  |  |
Options exercised | (905,464) |  | $ | 6.93 |  |  |  |  |
Options forfeited | (1,400,349) |  | $ | 16.13 |  |  |  |  |
Outstanding as of December 31, 2014 | 11,441,646 |  | $ | 10.73 |  |  |  |  |
Options granted | 362,335 |  | $ | 11.27 |  |  |  |  |
Options exercised | (1,184,141) |  | $ | 7.42 |  |  |  |  |
Options forfeited | (1,624,823) |  | $ | 17.22 |  |  |  |  |
Outstanding as of December 31, 2015 | 8,995,017 |  | $ | 10.01 |  |  | 5.4 |  | $ | 32,865 |
Vested or expected to vest at December 31, 2015 | 8,598,752 |  | $ | 10.14 |  |  | 5.3 |  | $ | 31,138 |
Options exercisable at December 31, 2015 | 5,638,184 |  | $ | 11.58 |  |  | 4.4 |  | $ | 18,386 |
Schedule of shares authorized under Stock Option Plans, by exercise price range | The following table summarizes the information about stock options outstanding and exercisable as of December 31, 2015:
| Options Outstanding |  | Options Exercisable
Range of Exercise Prices | Number Outstanding |  | Weighted Average Remaining Contractual Life (in years) |  | Weighted Average Exercise Price |  | Number Exercisable |  | Weighted Average Exercise Price
$4.13 – $5.39 | 901,728 |  | 6.0 |  | $ | 4.35 |  |  | 125,244 |  | $ | 4.81 |
$5.46 – $5.46 | 957,421 |  | 6.6 |  | $ | 5.46 |  |  | 638,284 |  |  | $ | 5.46 |
$5.49 – $5.63 | 885,485 |  | 3.1 |  | $ | 5.63 |  |  | 876,781 |  | $ | 5.63 |
$5.76 – $5.76 | 1,210,505 |  | 6.5 |  | $ | 5.76 |  |  | 522,321 |  | $ | 5.76 |
$6.39 – $8.55 | 1,007,877 |  | 4.8 |  | $ | 7.73 |  |  | 940,226 |  | $ | 7.75 |
$8.73 – $8.73 | 51,308 |  | 7.8 |  | $ | 8.73 |  |  | 16,781 |  | $ | 8.73 |
$8.76 – $8.76 | 1,291,345 |  | 7.7 |  | $ | 8.76 |  |  | 536,793 |  | $ | 8.76 |
$9.18 – $12.30 | 941,079 |  | 8.0 |  | $ | 11.25 |  |  | 308,564 |  | $ | 11.15 |
$12.33 – $19.86 | 981,013 |  | 2.3 |  | $ | 18.01 |  |  | 911,222 |  | $ | 18.29 |
$20.93 – $40.80 | 767,256 |  | 1.7 |  | $ | 27.55 |  |  | 761,968 |  | $ | 27.60 |
$4.13 – $40.80 | 8,995,017 |  | 5.4 |  | $ | 10.01 |  |  | 5,638,184 |  | $ | 11.58 |
Weighted-average assumptions for Stock Option Plans | 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 Plans for Years Ended December 31,
| 2015 |  | 2014 |  | 2013
Stock Option Plans |  |  |  |  |
Expected stock price volatility | 41% |  | 40%-44% |  | 45%-47%
Risk free interest rate | 1.2% |  | 2.1%-2.2% |  | 0.8%-1.5%
Expected term (in years) | 6.0 |  | 6.0-6.1 |  | 5.4-5.5
Weighted-average fair value of stock options granted | $4.59 |  | $4.26 |  | $2.60
Weighted-average assumptions for Employee Stock Purchase Plan |
| Employee Stock Purchase Plan for Years Ended December 31,
| 2015 |  | 2014 |  | 2013
Employee Stock Purchase Plan |  |  |  |  |
Expected stock price volatility | 34%-42% |  | 39%-44% |  | 44%-48%
Risk free interest rate | 0.1%-0.3% |  | 0.0%-0.1% |  | 0.1%
Expected term (in years) | 0.5 |  | 0.02-0.5 |  | 0.5
Weighted-average fair value of purchase rights granted under the purchase plan | $3.06 |  | $3.57 |  | $1.96
Activity related to nonvested equity stock and stock units | The following table reflects the activity related to nonvested equity stock and stock units for the three years ended December 31, 2015:
Nonvested Equity Stock and Stock Units | Shares |  | Weighted-Average Grant-Date Fair Value
Nonvested at December 31, 2012 | 922,491 |  | $ | 10.24 |
Granted | 473,074 |  | $ | 6.92 |
Vested | (478,214) |  | $ | 9.81 |
Forfeited | (287,702) |  | $ | 9.18 |
Nonvested at December 31, 2013 | 629,649 |  | $ | 8.56 |
Granted | 390,502 |  | $ | 10.40 |
Vested | (262,580) |  | $ | 9.85 |
Forfeited | (83,707) |  | $ | 7.69 |
Nonvested at December 31, 2014 | 673,864 |  | $ | 9.23 |
Granted | 2,865,878 |  | $ | 11.62 |
Vested | (276,622) |  | $ | 9.94 |
Forfeited | (255,002) |  | $ | 10.64 |
Nonvested at December 31, 2015 | 3,008,118 |  | $ | 11.32 |

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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6415400&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 of option exercise prices, by grouped ranges, including the upper and lower limits of the price range, the number of shares under option, weighted average exercise price and remaining contractual option terms. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6415400&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration