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STOCK-BASED COMPENSATION PLANS (Tables) | 12 Months Ended
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Dec. 31, 2019
Share-based Payment Arrangement [Abstract] |
Schedule of activity related to outstanding stock options | The activity related to the Company's outstanding stock options during the year ended December 31, 2019 was as follows:
| Number of Shares |  | Weighted Average Exercise Price |  | Weighted Average Remaining Contractual Term (years) |  | Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2019 | 582,061 |  |  | $ | 9.01 |  |  |  |  |
Granted | — |  |  | $ | — |  |  |  |  |
Exercised | (127,334 | ) |  | $ | 1.85 |  |  |  |  |
Forfeited | (38,666 | ) |  | $ | 2.55 |  |  |  |  |
Expired | (118,937 | ) |  | $ | 12.43 |  |  |  |  |
Outstanding at December 31, 2019 | 297,124 |  |  | $ | 11.55 |  |  | 4.95 |  | $ | 122 |
Vested or expected to vest at December 31, 2019 | 293,782 |  |  | $ | 11.65 |  |  | 4.92 |  | $ | 119 |
Exercisable at December 31, 2019 | 260,152 |  |  | $ | 12.89 |  |  | 4.59 |  | $ | 85 |
Schedule of assumptions used to estimate the fair value of options at the date of grant using the Black-Scholes option pricing model | The grant date fair values of stock options granted in the year ended December 31, 2017 were estimated using the Black-Scholes valuation model with the following assumptions:
Risk-free interest rate |  | 1.22% - 1.95%
Expected dividends |  | —
Weighted average volatility |  | 51.1%
Expected life (years) |  | 5.0
Schedule of activity related to unvested restricted stock grants | The activity related to the Company's RSAs for the year ended December 31, 2019 was as follows:
| Shares |  | Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2019 | 1,508,011 |  |  | $ | 6.90 |
Granted | — |  |  | $ | — |
Vested | (967,291 | ) |  | $ | 6.90 |
Forfeited | (52,744 | ) |  | $ | 7.04 |
Unvested balance at December 31, 2019 | 487,976 |  |  | $ | 6.87 |
The activity related to the Company's RSUs for the year ended December 31, 2019 was as follows:
| Shares |  | Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2019 | 636,300 |  |  | $ | 6.52 |
Granted | 2,828,832 |  |  | $ | 4.98 |
Vested | (537,416 | ) |  | $ | 6.04 |
Forfeited | (137,656 | ) |  | $ | 5.35 |
Unvested balance at December 31, 2019 | 2,790,060 |  |  | $ | 5.11 |
Schedule of activity related to performance stock awards | The activity related to the Company's PSUs for the year ended December 31, 2019 was as follows:
| Shares |  | Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2019 | 210,416 |  |  | $ | 5.77 |
Granted | 872,073 |  |  | $ | 6.03 |
Vested | (9,466 | ) |  | $ | 8.55 |
Forfeited | (5,950 | ) |  | $ | 8.55 |
Unvested balance at December 31, 2019 | 1,067,073 |  |  | $ | 5.94 |
Schedule of stock-based compensation expenses which are included in condensed consolidated statement of operations | The consolidated statements of operations included stock-based compensation for the years ended December 31, 2019, 2018 and 2017 as follows (in thousands):
| Year ended December 31,
| 2019 |  | 2018 |  | 2017
Product cost of revenue | $ | 76 |  |  | $ | 114 |  |  | $ | 514 |
Service cost of revenue | 478 |  |  | 345 |  |  | 1,448 |
Research and development | 1,898 |  |  | 1,797 |  |  | 7,337 |
Sales and marketing | 3,028 |  |  | 2,935 |  |  | 4,885 |
General and administrative | 7,121 |  |  | 5,881 |  |  | 11,473 |
| $ | 12,601 |  |  | $ | 11,072 |  |  | $ | 25,657 |
Schedule of common stock reserved for future issuance | Common stock reserved for future issuance at December 31, 2019 consists of the following:
2019 Plan | 7,051,559 |
ESPP | 1,148,867 |
| 8,200,426 |

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- 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=116856206&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=116856206&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=116856206&loc=d3e5070-113901 + Details
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