Common Stock (Tables)
|
3 Months Ended |
12 Months Ended |
Mar. 31, 2017 |
Dec. 31, 2016 |
| Equity [Abstract] |
|
|
| Summary of Stock Options Activity |
Stock option transactions and the number of stock options
outstanding are summarized below:
|
|
|
|
|
|
|
|
|
| |
|
Number of
Optioned
Common
Shares |
|
|
Weighted
Average
Exercise
Price |
|
|
Balance, December 31, 2016
|
|
|
1,378,805 |
|
|
$ |
8.62 |
|
|
Granted
|
|
|
— |
|
|
|
— |
|
|
Expired
|
|
|
(9,446 |
) |
|
|
21.05 |
|
|
Exercised
|
|
|
— |
|
|
|
— |
|
|
Forfeited
|
|
|
(30,173 |
) |
|
|
5.75 |
|
|
|
|
|
|
|
|
|
|
|
Balance, March 31, 2017
|
|
|
1,339,186 |
|
|
$ |
8.59 |
|
|
Stock option transactions and the number of stock options
outstanding are summarized below:
|
|
|
|
|
|
|
|
|
| |
|
Number of
Optioned
Common
Shares |
|
|
Weighted
Average
Exercise
Price |
|
|
Balance, January 1, 2014
|
|
|
1,007,491 |
|
|
$ |
11.39 |
|
|
Granted
|
|
|
382,097 |
|
|
|
8.97 |
|
|
Expired
|
|
|
(12,169 |
) |
|
|
18.93 |
|
|
Exercised
|
|
|
(10,000 |
) |
|
|
3.00 |
|
|
Forfeited
|
|
|
(84,000 |
) |
|
|
12.14 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2014
|
|
|
1,283,419 |
|
|
$ |
10.55 |
|
|
Granted
|
|
|
502,047 |
|
|
|
1.91 |
|
|
Expired
|
|
|
(247,766 |
) |
|
|
2.96 |
|
|
Exercised
|
|
|
(5,359 |
) |
|
|
2.69 |
|
|
Forfeited
|
|
|
(53,120 |
) |
|
|
14.37 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2015
|
|
|
1,479,221 |
|
|
$ |
8.78 |
|
|
Granted
|
|
|
1,635,250 |
|
|
|
0.86 |
|
|
Expired
|
|
|
(994,059 |
) |
|
|
1.00 |
|
|
Exercised
|
|
|
— |
|
|
|
— |
|
|
Forfeited
|
|
|
(741,607 |
) |
|
|
1.96 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2016
|
|
|
1,378,805 |
|
|
$ |
8.62 |
|
|
| Summary of Fair Value of Option Awards |
The fair value of each stock award for employees and directors is
estimated on the grant date and for consultants at each reporting
period, using the Black-Scholes option-pricing model based on the
weighted-average assumptions noted in the following table:
|
|
|
|
|
|
|
|
|
| |
|
Three Months
Ended March 31, |
|
| |
|
2017 |
|
|
2016 |
|
|
Risk-free interest rates
|
|
|
— |
|
|
|
1.52 |
% |
|
Expected dividend yield
|
|
|
— |
|
|
|
0 |
% |
|
Expected life
|
|
|
— |
|
|
|
5.3 years |
|
|
Expected volatility
|
|
|
— |
|
|
|
71.80 |
% |
|
The estimated fair value of stock options granted in the respective
periods was determined using the Black-Scholes option pricing model
using the following weighted average assumptions:
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
Risk-free interest rates
|
|
|
1.51 |
% |
|
|
1.76 |
% |
|
|
1.83 |
% |
|
Expected dividend yield
|
|
|
0 |
% |
|
|
0 |
% |
|
|
0 |
% |
|
Expected life
|
|
|
5.3 years |
|
|
|
5.8 years |
|
|
|
5.9 years |
|
|
Expected volatility
|
|
|
72 |
% |
|
|
63 |
% |
|
|
82 |
% |
|
| Summary of Share-Based Compensation Expense |
The results for the periods set forth below included share-based
compensation expense for stock options and restricted stock units
in the following expense categories of the consolidated statements
of loss (in thousands):
|
|
|
|
|
|
|
|
|
| |
|
Three Months
Ended
March 31, |
|
| |
|
2017 |
|
|
2016 |
|
|
Research and development
|
|
$ |
70 |
|
|
$ |
222 |
|
|
General and administrative
|
|
$ |
141 |
|
|
|
246 |
|
|
|
|
|
|
|
|
|
|
|
Total stock-based compensation
|
|
$ |
211 |
|
|
$ |
468 |
|
|
|
|
|
|
|
|
|
|
|
The results for the periods set forth below included stock-based
compensation expense in the following expense categories of the
consolidated statements of loss (in thousands):
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
Years ended December 31,
|
|
| |
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
Research and development
|
|
$ |
803 |
|
|
$ |
1,111 |
|
|
$ |
1,893 |
|
|
General and administrative
|
|
|
846 |
|
|
|
1,217 |
|
|
|
1,967 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Total stock-based compensation
|
|
$ |
1,649 |
|
|
$ |
2,328 |
|
|
$ |
3,860 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Summary of Restricted Stock Unit Award Activity |
The following table summarizes our restricted stock unit award
activity during the three months ended March 31, 2017:
|
|
|
|
|
|
|
|
|
| |
|
Number of
Shares |
|
|
Weighted
Average
Grant
Date Fair
Value |
|
|
Balance, December 31, 2016
|
|
|
253,221 |
|
|
$ |
4.56 |
|
|
Vested
|
|
|
(93,175 |
) |
|
|
5.95 |
|
|
Forfeited or expired
|
|
|
(18,329 |
) |
|
|
3.68 |
|
|
|
|
|
|
|
|
|
|
|
Balance, March 31, 2017
|
|
|
141,717 |
|
|
$ |
3.71 |
|
|
The following table summarizes our restricted stock unit award
activity during the years ended December 31, 2016, 2015 and
2014:
|
|
|
|
|
|
|
|
|
| |
|
Number of
Shares |
|
|
Weighted
Average
Grant Date
Fair Value |
|
|
Balance, January 1, 2014
|
|
|
356,589 |
|
|
$ |
12.06 |
|
|
Granted
|
|
|
814,800 |
|
|
|
6.48 |
|
|
Vested
|
|
|
(199,887 |
) |
|
|
7.00 |
|
|
Forfeited or expired
|
|
|
(291,301 |
) |
|
|
10.93 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2014
|
|
|
680,201 |
|
|
$ |
7.34 |
|
|
Granted
|
|
|
249,775 |
|
|
|
1.92 |
|
|
Vested
|
|
|
(269,401 |
) |
|
|
8.08 |
|
|
Forfeited or expired
|
|
|
(19,816 |
) |
|
|
7.27 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2015
|
|
|
640,759 |
|
|
$ |
4.92 |
|
|
Granted
|
|
|
— |
|
|
|
— |
|
|
Vested
|
|
|
(217,296 |
) |
|
|
5.23 |
|
|
Forfeited or expired
|
|
|
(170,242 |
) |
|
|
5.07 |
|
|
|
|
|
|
|
|
|
|
|
Balance, December 31, 2016
|
|
|
253,221 |
|
|
$ |
4.56 |
|
|
| Summary of Outstanding Warrants |
The following is a summary of outstanding warrants to purchase
common stock at March 31, 2017:
|
|
|
|
|
|
|
|
|
|
|
| |
|
Total
Outstanding
and
Exercisable |
|
|
Exercise
price per
Share |
|
|
Expiration
Date |
|
(1) Series A Warrants issued in July 2014 financing
|
|
|
2,779,933 |
|
|
|
4.00 |
|
|
July 2019 |
|
(2) Series B Warrants issued in July 2014 financing
|
|
|
670,269 |
|
|
|
4.00 |
|
|
July 2019 |
|
(3) Series A-1 Warrants issued in April 2015 financing
|
|
|
239,234 |
|
|
|
2.40 |
|
|
October 2020 |
|
The following is a summary of outstanding warrants to purchase
common stock at December 31, 2016:
|
|
|
|
|
|
|
|
|
|
|
| |
|
Total
Outstanding
and
Exercisable
|
|
|
Exercise
price per
Share |
|
|
Expiration
Date |
|
(1) Series A Warrants issued in July 2014 financing
|
|
|
2,779,933 |
|
|
|
4.00 |
|
|
July 2019 |
|
(2) Series B Warrants issued in July 2014 financing
|
|
|
670,269 |
|
|
|
4.00 |
|
|
July 2019 |
|
(3) Series A-1 Warrants issued in April 2015 financing
|
|
|
239,234 |
|
|
|
2.40 |
|
|
October 2020 |
|
| Summary of Fair Value of Warrants Issued |
The estimated fair value of warrants issued and classified as
liabilities is reassessed at each reporting date using the
Black-Scholes option pricing model.
|
|
|
|
|
|
|
|
|
| |
|
As of March 31, |
|
|
Series A and Series B Warrant Valuation Assumptions
|
|
2017 |
|
|
2016 |
|
|
Risk-free interest rates
|
|
|
1.32 |
% |
|
|
0.91 |
% |
|
Expected dividend yield
|
|
|
0 |
% |
|
|
0 |
% |
|
Expected life
|
|
|
2.25 years |
|
|
|
3.25 years |
|
|
Expected volatility
|
|
|
99.83 |
% |
|
|
84.07 |
% |
|
The following assumptions were used to value the warrants that are
classified as liabilities on the following reporting dates:
|
|
|
|
|
|
|
|
|
| |
|
As of December 31, |
|
| Series A and Series B Warrant Valuation
Assumptions |
|
2016 |
|
|
2015 |
|
|
Risk-free interest rates
|
|
|
1.33 |
% |
|
|
1.42 |
% |
|
Expected dividend yield
|
|
|
0 |
% |
|
|
0 |
% |
|
Expected life
|
|
|
2.50 years |
|
|
|
3.50 years |
|
|
Expected volatility
|
|
|
95 |
% |
|
|
77 |
% |
|
| Schedule of Common Stock |
|
Gross proceeds of $24.0 million and underwriting discounts and
commissions and offering expenses of $1.6 million were allocated as
follows:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
Common
Stock |
|
|
Series B
Pre-funded
Common
Stock
Warrants |
|
|
Series A
Common
Stock
Warrants |
|
|
Series B
Common
Stock
Warrants |
|
|
Units Issued
|
|
|
5,559,866 |
|
|
|
1,340,538 |
|
|
|
2,779,933 |
|
|
|
670,269 |
|
|
Gross Proceeds (in thousands)
|
|
$ |
14,084 |
|
|
$ |
3,387 |
|
|
$ |
5,261 |
|
|
$ |
1,268 |
|
|
Underwriting discount and offering expense (in thousands)
|
|
$ |
885 |
|
|
$ |
213 |
|
|
$ |
428 |
|
|
$ |
103 |
|
|
| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options |
|
(1) Number of common shares issuable upon
exercise of outstanding options:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Exercise Prices
|
|
Number of
Options
|
|
|
Weighted-
Average
Exercise Price |
|
|
Weighted-
Average
Remaining
Contractual
Life (in
years) |
|
|
$1.00 - $1.54
|
|
|
122,010 |
|
|
$ |
1.00 |
|
|
|
9.36 |
|
|
$1.55 - $1.88
|
|
|
337,298 |
|
|
|
1.86 |
|
|
|
7.96 |
|
|
$1.89 - $3.40
|
|
|
118,874 |
|
|
|
2.62 |
|
|
|
6.98 |
|
|
$3.41 - $11.70
|
|
|
78,447 |
|
|
|
7.70 |
|
|
|
5.72 |
|
|
$11.71 - $11.86
|
|
|
185,105 |
|
|
|
11.79 |
|
|
|
6.66 |
|
|
$11.87 - $11.99
|
|
|
144,699 |
|
|
|
11.95 |
|
|
|
5.64 |
|
|
$12.00 - $13.08
|
|
|
132,650 |
|
|
|
12.88 |
|
|
|
4.97 |
|
|
$13.09 - $16.40
|
|
|
135,576 |
|
|
|
15.64 |
|
|
|
3.54 |
|
|
$16.41 - $21.67
|
|
|
63,446 |
|
|
|
17.74 |
|
|
|
3.56 |
|
|
$21.68 - $22.28
|
|
|
60,700 |
|
|
|
22.28 |
|
|
|
2.67 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1,378,805 |
|
|
$ |
8.62 |
|
|
|
6.30 |
|
|
| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Vested Options |
|
(2) Number common shares issuable upon exercise
of vested options:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Exercise Prices
|
|
Number of
Options
|
|
|
Weighted-
Average
Exercise Price |
|
|
Weighted-
Average
Remaining
Contractual
Life
(in years) |
|
|
$1.00 - $1.54
|
|
|
510 |
|
|
$ |
1.21 |
|
|
|
0.42 |
|
|
$1.55 - $1.88
|
|
|
184,008 |
|
|
|
1.86 |
|
|
|
7.74 |
|
|
$1.89 - $3.40
|
|
|
90,275 |
|
|
|
2.51 |
|
|
|
6.76 |
|
|
$3.41 - $11.70
|
|
|
75,217 |
|
|
|
7.69 |
|
|
|
5.78 |
|
|
$11.71 - $11.86
|
|
|
140,269 |
|
|
|
11.79 |
|
|
|
6.58 |
|
|
$11.87 - $11.99
|
|
|
141,951 |
|
|
|
11.95 |
|
|
|
5.64 |
|
|
$12.00 - $13.08
|
|
|
132,650 |
|
|
|
12.88 |
|
|
|
4.97 |
|
|
$13.09 - $16.40
|
|
|
135,503 |
|
|
|
15.64 |
|
|
|
3.54 |
|
|
$16.41 - $21.67
|
|
|
63,446 |
|
|
|
17.74 |
|
|
|
3.56 |
|
|
$21.68 - $22.28
|
|
|
60,700 |
|
|
|
22.28 |
|
|
|
2.67 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1,024,529 |
|
|
$ |
10.54 |
|
|
|
5.58 |
|
|
| Computation of Basic and Diluted Net Loss Attributable to Common Shareholders Per Share |
|
The following table presents the computation of basic and diluted
net loss attributable to common stockholders per share (in
thousands, except per share and share amounts):
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
Years ended
December 31, |
|
| |
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
Numerator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net loss
|
|
$ |
(20,129 |
) |
|
$ |
(16,801 |
) |
|
$ |
(26,240 |
) |
|
Denominator
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Weighted average number of common shares outstanding
|
|
|
29,949,432 |
|
|
|
26,147,344 |
|
|
|
18,098,799 |
|
|
Basic and diluted net loss per common share
|
|
$ |
(0.67 |
) |
|
$ |
(0.64 |
) |
|
$ |
(1.45 |
) |
|