The Company's Amended and Restated 2019 Incentive Award Plan (the "2019 Plan") provides for the award of options to purchase the Company's common stock ("stock options"), stock appreciation rights ("SARs"), restricted stock awards ("RSAs"), performance-based stock awards ("PSAs"), restricted stock units ("RSUs"), performance-based stock units ("PSUs") and other stock- or cash-based awards. Awards can be granted under the 2019 Plan to the Company's employees, officers and non-employee directors, as well as consultants and advisors of the Company and its subsidiaries.

The Company's 2007 Plan provided for the award of stock options, SARs, RSAs, PSAs, RSUs, PSUs and other stock-based awards to employees, officers, non-employee directors, consultants and advisors of the Company and its subsidiaries. On and following June 5, 2019, with the exception of shares underlying awards outstanding as of that date, no additional shares may be granted under the 2007 Plan.

In connection with the acquisition of Edgewater Networks, Inc. in August 2018, the Company assumed Edgewater's Amended and Restated 2002 Stock Option Plan (the "Edgewater Plan") to the extent of the shares underlying the options outstanding under the Edgewater Plan as of the Edgewater Acquisition Date (the "Edgewater Options"). The Edgewater Options were converted to Ribbon stock options (the "Ribbon Replacement Options") which are vesting under the same schedules as the respective Edgewater Options.

In connection with the Company's acquisitions of Performance Technologies Inc. ("PT") in 2014, and Network Equipment Technologies, Inc. ("NET") in 2012, the Company assumed their stock plans (collectively, the "Assumed Plans"). Any outstanding awards under the Assumed Plans that in the future expire, terminate, are cancelled or surrendered, or are repurchased by the Company will be returned to the 2019 Plan. Accordingly, no additional shares may be granted under the Assumed Plans.

In connection with his appointment as President and Chief Executive Office of Ribbon, and as an inducement for Bruce McClelland's ("Mr. McClelland") commencement of employment, the Company awarded Mr. McClelland sign-on equity grants, comprised of an RSU grant and a PSU grant with both market and service conditions (the "Inducement PSUs") on March 16, 2020. Subject to Mr. McClelland's continued employment, 462,963 RSUs are eligible to vest on the earlier of March 16, 2021 or the date of the consummation of a change in control of the Company and, upon vesting, will be settled in shares of Ribbon's common stock. The RSUs had a fair market value of $1.0 million on the date of grant. Subject to Mr. McClelland's continued employment, the PSUs are eligible to vest and be settled in up to 4,750,000 shares of Ribbon common stock upon the achievement of specified share price thresholds on or prior to September 1, 2024. These grants are reported in the applicable tables below.

Each executive's 2020 Performance PSU grant is comprised of three consecutive fiscal year performance periods from 2020 through 2022 (each, a "fiscal year performance period"), with one-third of the 2020 Performance PSUs attributable to each fiscal year performance period. The number of shares that will vest, if any, for each fiscal year performance period will be based on the achievement of certain metrics related to the Company's financial performance for the applicable year on a standalone basis (each, a "fiscal year performance condition"). During the second quarter of 2020, the Company determined that the grant date criteria for the 2020 fiscal year performance period had been met, and recorded the applicable stock-based compensation expense. The grant date criteria for the 2021 and 2022 fiscal year performance periods had not been met as of September 30, 2020, and accordingly, no expense has been recorded for the 2020 Performance PSUs underlying these fiscal year performance periods. The number of shares of common stock to be achieved upon vesting of the 2020 Performance PSUs will in no event exceed 200% of the total 2020 Performance PSUs. Shares subject to the 2020 Performance PSUs that fail to be earned will be forfeited.

The 2020 Market PSUs have one three-year performance period which will end on December 31, 2022 (the "20-22 Market Performance Period"). The number of shares subject to the 2020 Market PSUs that will vest, if any, on June 15, 2023, will be dependent upon the Company's total shareholder return ("TSR") compared with the TSR of the companies included in the Nasdaq Telecommunications Index for the same 20-22 Market Performance Period, measured by the Compensation Committee after the 20-22 Market Performance Period ends. The shares determined to be earned will vest on June 15, 2023, pending each executive's continued employment with the Company through that date. The number of shares of common stock to be achieved upon vesting of the 2020 Market PSUs will in no event exceed 200% of the 2020 Market PSUs. Shares subject to the 2020 Market PSUs that fail to be earned will be forfeited.

In addition, in connection with his appointment as Executive Vice President and General Manager, Packet Optical Networking, the Company granted Sam Bucci 133,333 PSUs (the "Bucci Stock Price PSUs") with both market and service conditions. Subject to Mr. Bucci's continued employment, the Bucci Stock Price PSUs are eligible to vest and be settled in shares of Ribbon's common stock upon the achievement of a specific share price threshold on or prior to January 31, 2022.

2019 through 2021 (each, a "fiscal year performance period"), with one-third of the 2019 Performance PSUs attributable to each fiscal year performance period. The number of shares that will vest, if any, for each fiscal year performance period will be based on the achievement of certain metrics related to the Company's financial performance for the applicable year on a standalone basis (each, a "fiscal year performance condition"). In the third quarter of 2019, the Company adjusted the 2019 Performance PSU fiscal 2019 goals to reflect the changes to the Company's calculation of certain metrics. There was no incremental expense in connection with this modification. In March 2020, the Compensation Committee determined that the 2019 fiscal year performance conditions had been satisfied at the 30.493% level. The Company's achievement of the 2019 fiscal year performance conditions (and the number of shares of Company common stock to vest as a result thereof) was measured on a linear sliding scale in relation to specific threshold, target and stretch performance conditions. During the second quarter of 2020, the Company determined that the grant date criteria for the 2020 fiscal year performance period had been met, and recorded the applicable stock-based compensation expense. The grant date criteria for the 2021 fiscal year performance period had not been met as of September 30, 2020, and accordingly, no expense has been recorded for the 2019 Performance PSUs underlying the 2020 fiscal year performance period. The number of shares of common stock to be achieved upon vesting of the 2019 Performance PSUs will in no event exceed 200% of the 2019 Performance PSUs. Shares subject to the 2019 Performance PSUs that fail to be earned will be forfeited.

The 2019 Market PSUs have one three-year performance period which will end on December 31, 2021 (the "19-21 Market Performance Period"). The number of shares subject to the Market PSUs that will vest, if any, on March 15, 2022, will be dependent upon the Company's TSR compared with the TSR of the companies included in the Nasdaq Telecommunications Index for the same 19-21 Market Performance Period, measured by the Compensation Committee after the 19-21 Market Performance Period ends. The shares determined to be earned will vest on March 15, 2022, pending each executive's continued employment with the Company through that date. The number of shares of common stock to be achieved upon vesting of the 2019 Market PSUs will in no event exceed 200% of the 2019 Market PSUs. Shares subject to the 2019 Market PSUs that fail to be earned will be forfeited.

In connection with the separation of two executives from the Company, certain of the 2019 Performance PSUs were accelerated and released in accordance with their employment agreements in the three months ended September 30, 2020, with the potential for a portion of the 2020 Performance PSUs and Market PSUs aggregating approximately 43,000 shares to be released to these former executives on a pro rata basis subject to the Company's achievement for the performance periods through their respective separation dates.

2018 PSU Grant. In May 2018, the Company granted Franklin Hobbs, the Company's former President and Chief Executive Officer ("Mr. Hobbs"), 195,000 PSUs with both performance and service conditions (the "2018 PSUs"). Of the 195,000 2018 PSUs, one-half of such PSUs were eligible to vest based on the achievement of two separate metrics related to the Company's 2018 financial performance (the "2018 Performance Conditions"). The Company's achievement of the 2018 Performance Conditions (and the number of shares of Company common stock to be received upon vesting as a result thereof) were measured on a linear sliding scale in relation to specific threshold, target and stretch performance conditions. The number of shares of common stock to be received upon vesting of the 2018 PSUs would in no event exceed 150% of the 2018 PSUs. The Compensation Committee determined that the performance metrics for all of the 2018 PSUs had been achieved at the 150% level, for a total of 292,500 shares eligible to be issued. In connection with Mr. Hobbs' separation from the Company effective December 31, 2019, the vesting schedule for the 2018 Shares earned was accelerated and the shares were released on January 30, 2020.

Accounting for Performance PSUs. Once the grant date criteria have been met for a Fiscal Year Performance Period, the Company records stock-based compensation expense for the respective underlying Performance PSUs based on its assessment of the probability that each performance condition will be achieved and the level, if any, of such achievement. The Compensation Committee determines the number of shares earned, if any, after the Company's financial results for each Fiscal Year Performance Period are finalized. Upon the determination by the Compensation Committee of the number of shares that will be received upon vesting of the Performance PSUs, such number of shares becomes fixed and the unamortized expense is recorded through the remainder of the service period, generally three years from the date of grant, at which time the total Performance PSUs earned, if any, will vest, pending each executive's continued employment with the Company through that date.

approach to model future stock price movements based upon the risk-free rate of return, the date of return, the volatility of each entity and the pair-wise covariance between each entity. These results are then used to calculate the grant date fair values of the respective PSUs. The Company is required to record expense for the PSUs with market conditions through their respective final vesting dates, regardless of the number of shares that are ultimately earned.

At September 30, 2020, the calculation of the grant date fair values of the 2020 Market PSUs granted on September 15, 2020 and the Bucci Stock Price PSUs had not been completed. The Company used a grant date fair value of $4.24, the closing stock price on the date of grant, to calculate expense attributable to the three months ended September 30, 2020 for the 2020 Market PSUs granted on September 15, 2020 and the Bucci Stock Price PSUs, and is also using this stock price for these PSUs in the table below. The Company expects that the Monte Carlo valuation work and finalization of the grant date fair value of the 2020 Market PSUs granted on September 15, 2020 and the Bucci Stock Price PSUs will occur in the fourth quarter of 2020. At that time, the Company will record a cumulative adjustment to expense and adjust the grant date fair value of these PSUs for subsequent reporting. The Company does not expect the cumulative adjustment to expense will have a material impact on its consolidated financial statements.

At June 30, 2020, the calculation of the grant date fair value of the 2020 Market PSUs granted prior to September 15, 2020 had not been completed. The Company used a grant date fair value of $4.37, the closing stock price on the date of grant, to calculate expense attributable to the three months ended June 30, 2020 for the 2020 Market PSUs. During the third quarter of 2020, the Monte Carlo valuation of these PSUs was completed and accordingly, the grant date fair value of these PSUs was finalized as of September 30, 2020. The Company recorded a cumulative adjustment to expense to account for the change in fair value of these PSUs, which adjustment did not have a material impact on its consolidated financial statements.

At March 31, 2020, the calculation of the grant date fair value of the Inducement PSUs had not been completed. The Company used a grant date fair value of $2.16, the closing stock price on the date of grant, to calculate expense attributable to the three months ended March 31, 2020 for the Inducement PSUs. During the second quarter of 2020, the Monte Carlo valuation of the Inducement PSUs was completed and accordingly, the grant date fair value of the Inducement PSUs was finalized as of June 30, 2020. The Company recorded a cumulative adjustment to expense to account for the change in fair value of the Inducement PSUs, which adjustment did not have a material impact on its consolidated financial statements.


	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2020	297,124	$	11.55
Granted	—	$	—


Exercised	(16,128)	$	1.77
Forfeited	(6,055)	$	2.78
Expired	(41,717)	$	15.78
Outstanding at September 30, 2020	233,224	$	11.70	4.10	$	157
Vested or expected to vest at September 30, 2020	232,800	$	11.71	4.10	$	157
Exercisable at September 30, 2020	224,173	$	12.09	4.00	$	140

The Company's Amended and Restated 2000 Employee Stock Purchase Plan ("ESPP") was designed to provide eligible employees of the Company and its participating subsidiaries an opportunity to purchase common stock of the Company through accumulated payroll deductions. The ESPP provided for six-month offering periods with the purchase price of the stock equal to 85% of the lesser of the closing market price on the first or last day of the offering period. The maximum number of shares of common stock an employee could purchase during each offering period was 500, subject to certain adjustments pursuant to the ESPP. The last purchase under the ESPP purchase period was made on November 28, 2019, and the ESPP expired on May 20, 2020.


	Three months ended				Nine months ended
	September 30, 2020		September 30, 2019		September 30, 2020		September 30, 2019
Product cost of revenue	$	57	$	26	$	123	$	62
Service cost of revenue	204		124		493		367
Research and development	868		521		2,164		1,359
Sales and marketing	1,189		721		2,952		2,265
General and administrative	1,651		1,093		4,435		4,101
	$	3,969	$	2,485	$	10,167	$	8,154