|
STATEMENTS OF CASH FLOWS (USD $)
|
12 Months Ended |
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
| Cash flows from operating activities: |
|
|
|
| Net loss |
$ (30,117,980) |
$ (47,485,437) |
$ (17,963,873) |
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Depreciation and amortization |
182,927 |
120,399 |
113,936 |
| Loss on retirement of equipment and furnishings |
1,220 |
2,595 |
42,267 |
| (Gain) loss on warrant liability |
(19,051,239) |
20,210,094 |
(2,766,704) |
| Unrealized foreign exchange gain |
(125,659) |
(118,438) |
0 |
| Stock-based compensation expense |
6,596,248 |
3,985,106 |
2,391,529 |
| Changes in assets and liabilities: |
|
|
|
| Receivable |
(1,901,766) |
(835) |
65,902 |
| Interest receivable |
(96,163) |
18,053 |
14,758 |
| Prepaid expenses and other current assets |
(2,126,771) |
(1,132,428) |
(173,245) |
| Accounts payable |
2,779,409 |
789,655 |
984,547 |
| Accrued expenses and other current liabilities |
3,303,967 |
(139,747) |
(1,753,767) |
| Net cash used in operating activities |
(40,555,807) |
(23,750,983) |
(19,044,650) |
| Cash flows from investing activities: |
|
|
|
| Proceeds from matured short-term investments |
38,584,980 |
24,000,000 |
23,125,442 |
| Purchase of short-term investments |
(57,121,593) |
(27,084,980) |
(29,067,770) |
| Purchases of equipment and furnishings |
(956,286) |
(41,809) |
(141,639) |
| Net cash (used in) investing activities |
(19,492,899) |
(3,126,789) |
(6,083,967) |
| Cash flows from financing activities: |
|
|
|
| Proceeds from common stock issued in public offering, net of fees |
80,535,401 |
24,094,530 |
21,476,815 |
| Proceeds from issuance of restricted stock to employee |
100 |
0 |
100 |
| Repurchase of Company's own stock for treasury |
(182,943) |
(117,070) |
0 |
| Net proceeds from exercise of stock options and warrants |
431,941 |
39,336 |
7,200 |
| Net cash provided by financing activities |
80,784,499 |
24,016,796 |
21,484,115 |
| Net increase (decrease) in cash and cash equivalents |
20,735,793 |
(2,860,976) |
(3,644,502) |
| Cash and cash equivalents at beginning of year |
11,483,112 |
14,344,088 |
17,988,590 |
| Cash and cash equivalents at end of year |
32,218,905 |
11,483,112 |
14,344,088 |
| Supplemental disclosures of non-cash financing activities: |
|
|
|
| Cashless warrant exercises |
133 |
0 |
0 |
| Repurchase of Company's own stock for treasury |
12,671 |
27,829 |
0 |
| Equipment and furnishings purchased but not paid |
23,282 |
3,360 |
1,506 |
| Supplemental disclosure of Cash Flow Information: |
|
|
|
| Cash paid during the year for income taxes |
$ 800 |
$ 800 |
$ 0 |