Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Tables)

v3.20.4
Stockholders' Equity (Tables)
12 Months Ended
Dec. 31, 2020
Equity [Abstract]  
Schedule of Share-Based Compensation Expense
The following table summarizes non-cash share-based compensation expense (in thousands):
December 31,
2020 2019 2018
Share-based compensation expense as a component of:
Research and development expenses $ 13,497  $ 9,641  $ 8,352 
General and administrative expenses 17,230  14,874  12,494 
$ 30,727  $ 24,515  $ 20,846 
Schedule of Stock Option Plan Activity
Following is a summary of our stock option plan activity and related information:
 
Shares
Weighted
Average
Exercise
Price
Weighted
Average
Remaining
Contractual
Term in
Years
Aggregate
Intrinsic
Value
(In  thousands)
Balance at January 1, 2018 1,876,332  $ 53.17  5.77 $ 157,340 
Granted 228,362  $ 162.00 
Exercised (358,162) $ 55.24 
Forfeited (10,228) $ 114.53 
Balance at December 31, 2018 1,736,304  $ 66.71  5.47 125,858 
Exercisable at December 31, 2018 1,313,374  $ 47.03  4.56 117,314 
Options vested and expected to vest as of December 31, 2018 1,736,304  $ 66.71  5.47 $ 125,858 
Granted 338,617  $ 116.69 
Exercised (112,011) $ 23.65 
Forfeited (6,531) $ 139.37 
Balance at December 31, 2019 1,956,379  $ 77.54  5.45 72,002 
Exercisable at December 31, 2019 1,454,726  $ 61.82  4.42 70,345 
Options vested and expected to vest as of December 31, 2019 1,956,379  $ 77.54  5.45 $ 72,002 
Granted 806,300  $ 92.93 
Exercised (156,845) $ 21.26 
Forfeited (44,012) $ 91.30 
Balance at December 31, 2020 2,561,822  $ 85.59  6.09 59,033 
Exercisable at December 31, 2020 1,611,830  $ 76.05  4.54 53,286 
Options vested and expected to vest as of December 31, 2020 2,561,822  $ 85.59  6.09 $ 59,033 
Schedule of Stock Option Plan Activity by Exercise Price Range
Following is a further breakdown of the options outstanding as of December 31, 2020:
 
Range of exercise prices
Options
outstanding
Weighted
average
remaining  life
in years
Weighted average
exercise price
Options
exercisable
Weighted average
exercise price
$10.05-$14.47
284,184  0.86 $ 13.08  270,184  $ 13.00 
$21.92-$56.26
344,629  2.88 $ 35.34  344,629  $ 35.34 
$63.58-$74.42
307,356  5.20 $ 71.96  220,650  $ 73.41 
$82.90-$95.35
185,033  6.23 $ 86.22  140,400  $ 86.32 
$95.68 305,106  9.12 $ 95.68  63,059  $ 95.68 
$97.92 4,976  5.02 $ 97.92  4,976  $ 97.92 
$98.20 270,850  9.26 $ 98.20  —  $ 98.20 
$100.02-$113.76
257,914  6.69 $ 104.12  220,092  $ 103.96 
$117.58 19,744  9.44 $ 117.58  —  $ 117.58 
$117.97-$195.91
582,030  7.56 $ 137.18  347,840  $ 141.38 
2,561,822  6.09 $ 85.59  1,611,830  $ 76.05 
Schedule of Stock Option Weighted-Average Assumptions
The assumptions used for the specified reporting periods and the resulting estimates of weighted-average grant date fair value per share of options granted:

  Year Ended December 31,
  2020 2019 2018
Risk-free interest rate
0.2%-1.4%
1.4%-2.6%
2.7%-3.0%
Expected volatility
47%-71%
40%-49%
33%-36%
Expected term
4.7 to 5.1 years
4.6 to 5.9 years
5.1 to 5.8 years
Schedule of Restricted Stock Activity
The following is a summary of our restricted stock activity and related information: 
Shares
Weighted-Average
Grant Date Fair
Value
Outstanding at January 1, 2018 133,294  $ 91.60 
Granted 62,133  $ 169.92 
Vested (61,989) $ 86.19 
Forfeited (1,165) $ 125.16 
Outstanding at December 31, 2018 132,273  $ 130.63 
Granted 118,498  $ 115.90 
Vested (102,846) $ 121.55 
Forfeited (666) $ 134.36 
Outstanding at December 31, 2019 147,259  $ 125.11 
Granted 111,306  $ 89.73 
Vested (52,363) $ 121.69 
Forfeited —  $ — 
Outstanding at December 31, 2020 206,202  $ 106.88