XML 32 R21.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation (Tables)
9 Months Ended
Sep. 30, 2018
Summary of Stock-based Compensation Expense Recognized

During the three and nine months ended September 30, 2018 and 2017, the Company recognized the following stock-based compensation expense (in thousands):

 

 

 

Three Months Ended September 30,

 

 

Nine Months Ended September 30,

 

 

 

2018

 

 

2017

 

 

2018

 

 

2017

 

Stock-based compensation expense by type of award:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Stock options

 

$

447

 

 

$

154

 

 

$

1,018

 

 

$

529

 

Restricted stock and restricted stock units

 

 

79

 

 

 

180

 

 

 

403

 

 

 

521

 

Employee stock purchase plan

 

 

224

 

 

 

10

 

 

 

570

 

 

 

38

 

Total stock-based compensation expense included

   in expenses

 

$

750

 

 

$

344

 

 

$

1,991

 

 

$

1,088

 

Stock-based compensation expense by line item:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Research and development expenses

 

$

325

 

 

$

85

 

 

$

720

 

 

$

302

 

General and administrative expenses

 

 

425

 

 

 

259

 

 

 

1,271

 

 

 

786

 

Total stock-based compensation expense included

   in expenses

 

$

750

 

 

$

344

 

 

$

1,991

 

 

$

1,088

 

 

 

Schedule of Unrecognized Stock-based Compensation Expense, Net of Estimated Forfeitures, by Type of Award and Weighted-average Recognition Period

The following table sets forth the Company’s unrecognized stock-based compensation expense, net of estimated forfeitures, by type of award and the weighted-average period over which that expense is expected to be recognized (in thousands, except for years):

 

 

 

As of September 30, 2018

 

 

 

Unrecognized

Expense,

Net of

Estimated

Forfeitures

 

 

Weighted-

average

Recognition

Period

(in years)

 

 

 

 

 

 

 

 

 

 

Type of award:

 

 

 

 

 

 

 

 

Stock options

 

$

2,378

 

 

 

2.59

 

Restricted stock and restricted stock units

 

$

541

 

 

 

2.15

 

 

Summary of Stock Option Activity

The following table summarizes stock option activity during the nine months ended September 30, 2018:

 

 

 

Shares Subject to Stock Options

 

 

Weighted-

Average

Exercise

Price

 

 

Weighted-

Average

Remaining

Contractual

Term (in years)

 

 

Aggregate Intrinsic Value

 

Options outstanding at December 31, 2017

 

 

1,575,864

 

 

$

2.68

 

 

 

 

 

 

 

 

 

Granted

 

 

628,500

 

 

$

5.89

 

 

 

 

 

 

 

 

 

Exercised

 

 

(171,567

)

 

$

2.31

 

 

 

 

 

 

 

1,332,000

 

Cancelled

 

 

(18,750

)

 

$

1.91

 

 

 

 

 

 

 

 

 

Options outstanding at September 30, 2018

 

 

2,014,047

 

 

$

3.72

 

 

 

8.29

 

 

 

27,584,000

 

Options exercisable at September 30, 2018

 

 

807,091

 

 

$

3.99

 

 

 

7.60

 

 

 

10,836,000

 

 

Schedule of Weighted Average Assumptions using Black-Scholes Option Pricing Model

the fair value of each employee option grant during the nine months ended September 30, 2018 was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:

 

 

 

Nine Months Ended September 30, 2018

 

Expected volatility

 

 

80.86

%

Expected term (in years)

 

 

6.00

 

Risk-free interest rate

 

 

2.55

%

Expected dividend yield

 

 

0

%

 

Restricted stock [Member]  
Summary of Stock Activity

The following table is a summary of restricted stock activity during the nine months ended September 30, 2018:

 

 

 

Shares of Restricted Stock

 

 

Weighted-

Average

Grant Date

Fair Value

 

Unvested at December 31, 2017

 

 

245,096

 

 

$

2.53

 

Granted

 

 

 

 

$

 

Vested

 

 

(62,001

)

 

$

9.49

 

Forfeited

 

 

 

 

$

 

Unvested at September 30, 2018

 

 

183,095

 

 

$

0.17

 

  

Restricted stock units [Member]  
Summary of Stock Activity

The following table summarizes restricted stock unit activity during the nine months ended September 30, 2018:

 

 

 

Shares Subject to Restricted Stock Units

 

 

Weighted-

Average

Grant Date

Value

 

Unvested at December 31, 2017

 

 

46,250

 

 

$

5.50

 

Granted

 

 

105,000

 

 

$

5.34

 

Vested

 

 

(13,125

)

 

$

8.78

 

Forfeited

 

 

 

 

$

 

Unvested September 30, 2018

 

 

138,125

 

 

$

5.07