Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation (Tables)

v3.19.3.a.u2
Stock-based Compensation (Tables)
12 Months Ended
Dec. 31, 2019
Share-based Payment Arrangement [Abstract]  
Schedule of stock-based compensation expense
Stock-based compensation expense is included in the consolidated statements of operations as follows (in thousands):
 
  Year Ended December 31,
  2019 2018 2017
Research and development $ 1,562    $ 2,055    $ 1,444   
Selling, general and administrative 5,381    5,834    5,647   
Total $ 6,943    $ 7,889    $ 7,091   
The following table presents total stock-based compensation expense by security type included in the consolidated statements of operations (in thousands):
  Year Ended December 31,
  2019 2018 2017
Stock options $ 2,149    $ 1,975    $ 1,554   
RSUs and RSAs 1,805    1,770    1,888   
PSUs 1,087    1,511    1,792   
PBOs 1,902    2,633    1,857   
Total $ 6,943    $ 7,889    $ 7,091   
Assumptions used to estimate the fair value of option grants The following summarize the ranges of weighted-average assumptions used to estimate the fair value of employee stock options granted:
  Year Ended December 31,
  2019 2018 2017
Expected life (years) 5.6 5.6 5.4
Volatility 55.3  % 60.0  % 62.2  %
Risk-free interest rate 2.4  % 2.7  % 2.0  %
Expected dividend yield 0.0  % 0.0  % 0.0  %
Schedule of share-based compensation, stock options, activity
The following tables summarizes stock option activities:
Number
of
Shares
Weighted
Average
Exercise Price Per Share
(In Thousands)
Outstanding at December 31, 2016 3,890    $ 4.40   
Granted
856    $ 4.57   
Exercised
(86)   $ 3.10   
Forfeited/Expired
(81)   $ 7.72   
Outstanding at December 31, 2017 4,579    $ 4.40   
Granted
645    $ 9.56   
Exercised
(772)   $ 5.56   
Forfeited/Expired
(340)   $ 6.66   
Outstanding at December 31, 2018 4,112    $ 4.81   
Granted 406    $ 20.68   
Exercised (1,045)   $ 4.50   
Forfeited/Expired (326)   $ 11.01   
Outstanding at December 31, 2019 3,147    $ 6.31   

Number
of
Shares
Weighted
Average
Exercise Price Per Share
Weighted
Average
Remaining
Contractual Term
Aggregate Intrinsic
Value
(In Thousands) (In Years) (In Thousands)
Outstanding at December 31, 2019 3,147    $ 6.31    5.6 $ 31,961   
Exercisable at December 31, 2019 2,415    $ 4.23    4.7 $ 28,406   
Vested and expected to vest at December 31, 2019 3,050    $ 6.05    5.5 $ 31,600   
Schedule of share-based compensation, RSA activity
The following table summarizes RSA activities:
Number
of
Shares
Weighted Average
Grant Date
Fair Value
Per Share
(In Thousands)  
Non-vested balance at December 31, 2016 230    $ 3.82   
Granted
143    $ 4.75   
Vested
(214)   $ 3.81   
Non-vested balance at December 31, 2017 159    $ 4.68   
Granted
47    $ 14.35   
Vested
(151)   $ 4.71   
Non-vested balance at December 31, 2018 55    $ 12.83   
Granted 40    $ 17.18   
Vested (56)   $ 12.83   
Forfeited/Expired (4)   $ 17.18   
Non-vested balance at December 31, 2019 35    $ 17.18   
Schedule of share-based compensation, RSU activity
The following table summarizes RSU activities:
Number
of
Shares
Weighted Average
Grant Date
Fair Value
Per Share
(In Thousands)  
Non-vested balance at December 31, 2016 617    $ 3.69   
Granted
275    $ 4.22   
Vested
(302)   $ 3.40   
Forfeited/Expired
(30)   $ 4.12   
Non-vested balance at December 31, 2017 560    $ 4.08   
Granted
86    $ 10.56   
Vested
(290)   $ 4.09   
Forfeited/Expired
(8)   $ 4.73   
Non-vested balance at December 31, 2018 348    $ 5.66   
Granted 72    $ 19.19   
Vested (210)   $ 5.03   
Forfeited/Expired (9)   $ 13.60   
Non-vested balance at December 31, 2019 201    $ 10.76   
Share-based compensation, performance shares award outstanding activity
The following table summarizes PSU activities:
Number
of
Shares
Weighted Average
Grant Date
Fair Value
Per Share
(In Thousands)  
Non-vested balance at December 31, 2016 831    $ 3.88   
Granted
276    $ 4.25   
Vested
(651)   $ 3.84   
Forfeited/Expired
(27)   $ 3.65   
Non-vested balance at December 31, 2017 429    $ 4.20   
Granted
306    $ 6.71   
Vested
(495)   $ 7.16   
Non-vested balance at December 31, 2018 240    $ 7.48   
Granted 95    $ 14.98   
Vested (200)   $ 6.58   
Forfeited/Expired
(15)   $ 15.58   
Non-vested balance at December 31, 2019 120    $ 13.88   
The following table summarizes PBO activities:
Number of Shares Weighted Average Grant Date Fair Value Per Share
(in thousands)  
Outstanding at December 31, 2016 —    $ —   
Granted 1,720    $ 2.54   
Outstanding at December 31, 2017 1,720    $ 2.54   
Granted
1,200    $ 5.02   
Exercised (84)   $ 2.54   
Forfeited (1,254)   $ 3.73   
Outstanding at December 31, 2018 1,582    $ 3.47   
Granted
718    $ 11.44   
Exercised
(422)   $ 3.17   
Forfeited
(618)   $ 10.34   
Outstanding at December 31, 2019 1,260    $ 4.75   

Number
of
Shares
Weighted
Average
Exercise Price Per Share
Weighted
Average
Remaining
Contractual Term
Aggregate Intrinsic
Value
(In Thousands) (In Years) (In Thousands)
Exercisable at December 31, 2019 863    $ 5.57    7.3 $ 8,993   
Vested and expected to vest at December 31, 2019 1,213    $ 8.47    7.7 $ 10,181   

The total fair value of exercised PBOs were $1.3 million for 2019, $0.2 million for 2018 and zero for 2017. As of December 31, 2019, there was $0.9 million of unrecognized stock-based compensation cost related to non-vested PBOs, which we expect to recognize over a weighted average period of 0.8 years.
Schedule of assumptions used The following summarize the ranges of weighted-average assumptions used to estimate the fair value of employee stock options granted:
  Year Ended December 31,
  2019 2018 2017
Expected life (years) 5.58 5.63 5.33
Volatility 55.8  % 60.3  % 62.3  %
Risk-free interest rate 2.5  % 2.7  % 2.0  %
Expected dividend yield 0.0  % 0.0  % 0.0  %