Consolidated Statements of Cash Flows - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Cash flows from operating activities: |
|
|
|
| Net loss |
$ (23,438)
|
$ (33,314)
|
$ (18,346)
|
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Depreciation and amortization |
553
|
689
|
752
|
| Derivatives (gain) loss |
(593)
|
10,804
|
376
|
| Common stock issued to 401(k) plan |
208
|
201
|
173
|
| Common stock issued for services |
|
|
477
|
| Share-based compensation expense |
5,063
|
4,666
|
2,730
|
| Other non-cash investment activities |
98
|
|
|
| Changes in operating assets and liabilities: |
|
|
|
| Restricted cash |
|
61
|
180
|
| Prepaid expenses |
(267)
|
888
|
(363)
|
| Insurance receivable |
|
|
(689)
|
| Other assets |
(324)
|
3
|
4
|
| Accounts payable |
489
|
(48)
|
(330)
|
| Accrued expenses |
1,471
|
(279)
|
(248)
|
| Net cash used in operating activities |
(16,740)
|
(16,329)
|
(15,284)
|
| Cash flows from investing activities: |
|
|
|
| Purchases of marketable securities |
(18,916)
|
(5,274)
|
|
| Sales of marketable securities |
12,515
|
|
|
| Non-cash disposals of property and equipment |
|
|
45
|
| Purchases of property and equipment |
(107)
|
(5)
|
(47)
|
| Net cash used in investing activities |
(6,508)
|
(5,279)
|
(2)
|
| Cash flows from financing activities: |
|
|
|
| Proceeds from exercise of stock options |
191
|
1,068
|
212
|
| Proceeds from issuance of stock under ESPP |
91
|
|
|
| Proceeds from exercise of warrants |
|
7,789
|
12
|
| Repayment of note payable |
|
(18)
|
(56)
|
| Principal payments on capital lease obligation |
|
|
(21)
|
| Repayment of loan payable |
(395)
|
(250)
|
|
| Proceeds from issuance of common stock and warrants |
29,905
|
14,480
|
14,618
|
| Net cash provided by financing activities |
29,792
|
23,069
|
14,765
|
| Increase (decrease) in cash and cash equivalents |
6,544
|
1,461
|
(521)
|
| Cash and cash equivalents at beginning of period |
14,920
|
13,459
|
13,980
|
| Cash and cash equivalents at end of period |
21,464
|
14,920
|
13,459
|
| Supplemental disclosure of cash flow information and non-cash investing and financing activities: |
|
|
|
| Cash paid for interest |
103
|
121
|
132
|
| Fair value of warrants issued in connection with underwriting agreement |
|
|
$ 6,848
|
| Cashless exercise of equity-classified warrants to common stock |
$ 90
|
251
|
|
| Reclassification of derivative warrant liability to additional paid-in capital |
|
$ 16,121
|
|