Consolidated Statements of Cash Flows - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Operating activities |
|
|
|
| Net loss |
$ (15,337)
|
$ (16,422)
|
$ (22,082)
|
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Depreciation |
382
|
267
|
360
|
| Gain from forgiveness of note payable |
(190)
|
|
|
| Stock-based compensation |
2,868
|
2,929
|
2,605
|
| Deferred tax benefit |
2
|
23
|
(200)
|
| Gain from insurance proceeds, net |
(682)
|
|
|
| Change in fair value of warrant liabilities |
557
|
(772)
|
(6,591)
|
| Changes in operating assets and liabilities: |
|
|
|
| Accounts receivable |
(237)
|
333
|
(174)
|
| Prepaid expenses and other |
(462)
|
4
|
(33)
|
| Accounts payable and accrued expenses |
2,413
|
(296)
|
335
|
| Deferred revenue |
(245)
|
170
|
(11)
|
| Net cash used in operating activities |
(10,931)
|
(13,764)
|
(25,791)
|
| Investing activities |
|
|
|
| Purchase of available-for-sale securities |
(16,343)
|
|
|
| Sales of available-for-sale securities |
16,305
|
|
|
| Proceeds from insurance |
682
|
|
|
| Purchases of equipment |
(1,711)
|
(132)
|
(297)
|
| Net cash used in investing activities |
(1,067)
|
(132)
|
(297)
|
| Financing activities |
|
|
|
| Proceeds from issuance of common stock and warrants, net |
4,028
|
10,310
|
19,621
|
| Proceeds from exercise of warrants |
163
|
976
|
938
|
| Purchase of treasury stock |
(467)
|
(490)
|
(292)
|
| Net cash provided by financing activities |
3,724
|
10,796
|
20,267
|
| Decrease in cash and cash equivalents |
(8,274)
|
(3,100)
|
(5,821)
|
| Cash and cash equivalents at beginning of year |
23,027
|
26,127
|
31,948
|
| Cash and cash equivalents at end of year |
$ 14,753
|
$ 23,027
|
$ 26,127
|