STOCK BASED COMPENSATION (Tables)
|
12 Months Ended |
Dec. 31, 2016 |
|---|
| Summary of restricted stock awards |
|
|
|
|
|
|
|
|
|
|
|
|
Weighted-Average
|
|
|
|
|
|
Purchase Price
|
|
|
|
Shares
|
|
per Share
|
|
Unvested at December 31, 2015
|
|
75,718
|
|
$
|
5.73
|
|
Granted
|
|
—
|
|
|
—
|
|
Vested
|
|
(32,453)
|
|
|
5.73
|
|
Unvested at December 31, 2016 (1)
|
|
43,265
|
|
$
|
5.73
|
|
| Summary of stock option activity |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted-
|
|
|
|
|
|
|
|
|
|
|
Weighted-
|
|
Average
|
|
|
|
|
|
|
|
|
|
|
Average
|
|
Remaining
|
|
|
Aggregate
|
|
|
|
|
|
|
|
Exercise Price
|
|
Contractual
|
|
|
Intrinsic
|
|
|
|
|
Shares
|
|
|
per Share
|
|
Term (in years)
|
|
|
Value
|
|
|
Outstanding at December 31, 2015
|
|
1,452,149
|
|
$
|
10.37
|
|
10.4
|
|
$
|
24,887
|
|
|
Granted
|
|
1,063,981
|
|
|
16.46
|
|
|
|
|
|
|
|
Exercised
|
|
(81,831)
|
|
|
5.41
|
|
|
|
|
|
|
|
Cancelled
|
|
(107,498)
|
|
|
16.05
|
|
|
|
|
|
|
|
Outstanding at December 31, 2016
|
|
2,326,801
|
|
$
|
13.07
|
|
8.7
|
|
$
|
7,927
|
|
|
Exercisable at December 31, 2016
|
|
556,040
|
|
$
|
9.19
|
|
8.0
|
|
$
|
3,917
|
|
|
Vested and expected to vest at December 31, 2016
|
|
2,291,971
|
|
$
|
13.11
|
|
8.7
|
|
$
|
8,090
|
|
|
| Schedule of weighted-average assumptions used in Black-Scholes option-pricing model |
|
|
|
|
|
|
|
|
|
|
|
|
Years ended December 31,
|
|
|
|
|
2016
|
|
2015
|
|
2014
|
|
|
Risk-free interest rate
|
|
1.5
|
%
|
1.7
|
%
|
1.8
|
%
|
|
Volatility
|
|
76.3
|
%
|
77.0
|
%
|
77.1
|
%
|
|
Expected term (years)
|
|
6.02
|
|
6.20
|
|
6.25
|
|
|
Expected dividend yield
|
|
—
|
%
|
—
|
%
|
—
|
%
|
|
| Schedule of stock-based compensation for all stock options and restricted stock awards |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Years ended December 31,
|
|
|
|
|
2016
|
|
|
2015
|
|
|
2014
|
|
Research and development
|
|
$
|
638
|
|
$
|
223
|
|
$
|
12
|
|
Selling, general and administrative
|
|
|
5,149
|
|
|
1,986
|
|
|
10
|
|
Total stock-based compensation expense
|
|
$
|
5,787
|
|
$
|
2,209
|
|
$
|
22
|
|
| Restricted Stock Units (RSUs) |
|
| Summary of restricted stock awards |
|
|
|
|
|
|
|
|
|
|
|
|
Weighted-Average
|
|
|
|
Shares
|
|
Grant Date Fair Value
|
|
Outstanding at December 31, 2015
|
|
—
|
|
$
|
—
|
|
Granted
|
|
41,741
|
|
|
16.15
|
|
Settled
|
|
—
|
|
|
—
|
|
Forfeited
|
|
—
|
|
|
—
|
|
Outstanding at December 31, 2016
|
|
41,741
|
|
$
|
16.15
|
|