STOCK-BASED COMPENSATION (Tables)
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12 Months Ended |
Dec. 31, 2019 |
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| STOCK-BASED COMPENSATION |
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| Schedule of stock-based compensation related to all of the entity's share-based payments |
Total stock‑based compensation expense related to all of our stock‑based awards was as follows (in thousands):
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Year Ended December 31,
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2019
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2018
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2017
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Selling, general and administrative
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$
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6,453
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$
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5,383
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$
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4,490
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Research and development
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2,662
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2,321
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1,497
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Total stock-based compensation expense
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$
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9,115
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$
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7,704
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$
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5,987
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| Summary of weighted-average assumptions relating to options granted pursuant to equity incentive plans |
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Year Ended
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December 31,
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2019
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2018
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2017
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Risk-free interest rate
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2.4
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%
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2.7
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%
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2.2
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%
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Expected term (in years)
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6.5
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6.7
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6.6
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Dividend yield
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0.0
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%
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0.0
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%
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0.0
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%
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Expected volatility
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65.5
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%
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65.1
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%
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63.5
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%
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| Schedule of option activity under equity incentive plans |
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Weighted-
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Average
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Remaining
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Shares Available
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Number of Shares
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Weighted-Average
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Contractual Term
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Aggregate
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For Grant
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Underlying Options
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Exercise Price
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(in years)
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Intrinsic Value
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Outstanding at January 1, 2019
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15,097,014
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20,713,331
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$
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4.20
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Authorized for grant
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3,544,984
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—
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Granted
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(7,457,575)
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7,457,575
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$
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2.03
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Exercised
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—
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(68,654)
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$
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2.05
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Cancelled
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5,431,548
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(5,431,548)
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$
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4.16
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Outstanding at December 31, 2019
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16,615,971
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22,670,704
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$
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3.51
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6.15
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$
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809,459
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Vested and expected to vest at December 31, 2019
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22,363,204
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$
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3.51
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Exercisable at December 31, 2019
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15,804,733
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$
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3.97
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5.10
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$
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243,612
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| Schedule of stock options by exercise price |
Details of our stock options by exercise price are as follows as of December 31, 2019:
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Options Outstanding
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Options Exercisable
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Number of
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Weighted-Average
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Outstanding
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Remaining
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Weighted-Average
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Number of
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Weighted-Average
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Exercise Price
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Options
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Contractual Life (in years)
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Exercise Price
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Options
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Exercise Price
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$1.68 - $1.96
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479,134
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9.51
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$
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1.95
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10,834
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$
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1.68
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$2.00 - $2.00
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4,426,817
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8.57
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2.00
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821,292
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2.00
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$2.02 - $2.14
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3,814,210
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5.97
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2.11
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3,433,546
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2.12
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$2.21 - $2.74
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3,621,639
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6.88
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2.52
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2,590,664
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2.62
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$2.76 - $3.80
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3,231,670
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5.83
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3.50
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2,676,557
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3.50
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$3.84 - $4.49
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3,777,761
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6.48
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4.32
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2,952,367
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4.31
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$4.53 - $9.62
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3,319,473
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1.63
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7.50
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3,319,473
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7.50
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$1.68 - $9.62
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22,670,704
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6.13
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3.51
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15,804,733
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3.97
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| Summary of weighted-average assumptions used to calculate fair value of purchase rights granted under Employee Stock Purchase Plan |
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Year Ended
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December 31,
|
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2019
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|
2018
|
|
2017
|
|
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Risk-free interest rate
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2.7
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%
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2.4
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%
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0.5
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%
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Expected term (in years)
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1.5
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1.3
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1.5
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Dividend yield
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0.0
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%
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0.0
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%
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0.0
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%
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Expected volatility
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62.6
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%
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66.2
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%
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63.1
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%
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