Share-based Compensation (Tables)
 3 Months Ended
Mar. 31, 2020
Share-based Payment Arrangement [Abstract]  
Schedule of Share-based Compensation Expense
During the periods presented, the Company recorded the following share-based compensation expense for stock options and restricted stock awards:
 
 
 
 
 
 
 
Three Months Ended March 31,
 
 
2020
 
2019
 
 
 
 
 
 
 
(in thousands)
Sales, general and administrative
 
$
1,307

 
$
1,268

Research and development
 
322

 
568

Total
 
$
1,629

 
$
1,836

 
 
 
 
 
Schedule of Stock Options
Stock Options
 
 
 
 
 
 
 
 
 
 
 
Number of Options Outstanding
 
Weighted-Average Exercise Price
 
Weighted-Average Remaining Contractual Term (in years)
 
Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2019
 
1,837,576

 
$
14.54

 
8.06
 
$
24,122

Granted (weighted-average fair value of $14.20 per share)
 
70,953

 
25.03

 
 
 
 
Exercised
 
(39,723
)
 
4.56

 
 
 
 
Forfeited/canceled
 
(87,375
)
 
14.43

 
 
 
 
Balances at March 31, 2020
 
1,781,431

 
$
15.18

 
8.00
 
$
6,232

 
 
 
 
 
 
 
 
 
Schedule of Employee Stock Options Valuation Assumptions
The fair value of stock options granted to consultants was estimated using the following assumptions during the following periods presented:
 
 
 
 
 
 
 
Three Months Ended March 31,
 
 
2020
 
2019
Volatility
 
56%
 
—
Risk-free interest rate
 
1.6%
 
—
Term (in years)
 
10
 
—
Dividend yield
 
—
 
—
 
 
 
 
 
The fair value of stock options granted to employees was estimated using the following assumptions:
 
 
 
 
 
 
 
Three Months Ended March 31,
 
 
2020
 
2019
Volatility
 
55%
 
56%
Risk-free interest rate
 
1.5%
 
2.5% - 2.6%
Term (in years)
 
6.25
 
6.25
Dividend yield
 
0%
 
0%
 
 
 
 
 
Schedule of Restricted Stock
The following table represents RSA activity for fiscal 2020:
 
 
 
 
 
 
 
Restricted Stock Awards
 
Weighted-
Average
Grant Date
Fair Value
Outstanding unvested at December 31, 2019
 
128,682

 
$
11.81

Granted
 
—

 
—

Vested
 
(11,062
)
 
12.82

Forfeited/canceled
 
(9,148
)
 
9.55

Outstanding unvested at March 31, 2020
 
108,472

 
$
11.90