v3.19.3

STOCKHOLDERS' EQUITY (Tables) | 9 Months Ended
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Sep. 30, 2019
Share-based Payment Arrangement [Abstract] |
Summary of Stock Option Activity | A summary of stock option activity for the nine months ended September 30, 2019 is as follows (in thousands, except share and per share data):
| Number of Stock Options Outstanding |  | Weighted Average Exercise Price |  | Weighted Average Remaining Contractual Term (in years) |  | Aggregate Intrinsic Value
Balance at December 31, 2018 | 33,152,881 |  |  | $ | 9.52 |  |  | 5.45 |  | $ | 1,543,793 |
Granted | 1,184,657 |  |  | 72.15 |  |  |  |  |
Exercised | (7,881,289 | ) |  | 7.97 |  |  |  |  |
Forfeited | (136,772 | ) |  | 11.70 |  |  |  |  |
Balance at September 30, 2019 | 26,319,477 |  |  | $ | 12.80 |  |  | 5.23 |  | $ | 1,305,789 |
Options exercisable as of September 30, 2019 | 24,136,540 |  |  | $ | 9.40 |  |  | 4.92 |  | $ | 1,269,509 |
Schedule of Restricted Stock Awards and Restricted Stock Units Activity | Activity related to RSAs and RSUs during the nine months ended September 30, 2019 is set forth below:
| Number of shares |  | Weighted Average Grant Date Fair Value
Unvested as of December 31, 2018 | 17,934,728 |  |  | $ | 31.34 |
Granted | 5,735,224 |  |  | 73.29 |
Vested | (6,016,950 | ) |  | 29.05 |
Forfeited | (1,727,904 | ) |  | 35.90 |
Unvested as of September 30, 2019 | 15,925,098 |  |  | $ | 46.82 |
Schedule of Fair Value Assumptions for Options | The fair value of stock options granted was estimated using the following weighted-average assumptions:
| Nine Months Ended September 30,
| 2019 |  | 2018
Dividend yield | — | % |  | — | %
Risk-free interest rate | 2.48 | % |  | 2.92 | %
Expected volatility | 39.52 | % |  | 30.87 | %
Expected term (years) | 6.05 |  |  | 6.19 |
Summary of the Effect of Share-Based Compensation on the Condensed Consolidated Statements of Operations | The following table summarizes the effects of share-based compensation on the Company's condensed consolidated statements of operations (in thousands):
| Three Months Ended September 30, |  | Nine Months Ended September 30,
| 2019 |  | 2018 |  | 2019 |  | 2018
Cost of revenue | $ | 38 |  |  | $ | 18 |  |  | $ | 88 |  |  | $ | 79 |
Product development | 56,321 |  |  | 39,525 |  |  | 155,114 |  |  | 103,813 |
Sales and marketing | 6,269 |  |  | 6,108 |  |  | 20,304 |  |  | 16,703 |
General and administrative | 14,798 |  |  | 13,262 |  |  | 42,474 |  |  | 37,261 |
Total | $ | 77,426 |  |  | $ | 58,913 |  |  | $ | 217,980 |  |  | $ | 157,856 |

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- Definition Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited 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 (c)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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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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- 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=116856206&loc=d3e5070-113901 + Details
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