|
Consolidated Statements of Cash Flows (USD $)
|
12 Months Ended |
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
| Cash flows from operating activities |
|
|
|
| Net loss |
$ (53,305,938) |
$ (23,921,563) |
$ (10,471,330) |
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Depreciation and amortization |
566,117 |
611,421 |
505,261 |
| Compensation expense related to stock options and warrants |
3,013,283 |
1,081,186 |
1,043,550 |
| Amortization of debt issuance costs |
69,308 |
|
|
| Amortization of debt discount |
24,917 |
|
|
| Interest accrued on long-term debt |
693,114 |
|
|
| Write-off of deferred financing costs |
|
|
1,785,779 |
| Derivative expense (income) |
|
|
(1,036,403) |
| Noncash interest expense |
|
2,465 |
292,064 |
| Increase (decrease) in fair value of warrant liability |
|
(355,352) |
(4,916,785) |
| Issuance of restricted stock recorded as consulting expense |
|
16,500 |
14,550 |
| Loss (gain) on disposal of equipment |
(1,710) |
(50,835) |
(4,774) |
| Changes in operating assets and liabilities: |
|
|
|
| Prepaid expenses and other receivables |
86,997 |
438,867 |
(216,332) |
| Deferred financing costs |
|
(571,327) |
|
| Other assets |
(10,471) |
|
|
| Accounts payable |
543,419 |
181,965 |
60,977 |
| Accrued expenses |
(395,416) |
1,244,940 |
(254,813) |
| Long-term portion of manufacturing research and development obligation |
3,475,552 |
|
|
| Deferred liability |
|
3,066,000 |
|
| Net cash used in operating activities |
(45,240,828) |
(18,255,733) |
(13,198,256) |
| Cash flows from investing activities |
|
|
|
| Purchases of property and equipment |
(1,097,798) |
(596,455) |
(1,137,533) |
| Proceeds from sales of fixed assets |
2,000 |
50,835 |
5,555 |
| Purchases of short-term investments |
(25,593,464) |
(13,600,941) |
(4,591,437) |
| Payment to restricted cash account securing letter of credit |
(1,325,000) |
|
|
| Proceeds from sales and maturities of short-term investments |
20,225,000 |
4,090,000 |
442,566 |
| Net cash (used in) provided by investing activities |
(7,789,262) |
(10,056,561) |
(5,280,849) |
| Cash flows from financing activities |
|
|
|
| Proceeds from sale of common stock |
49,829,800 |
|
|
| Proceeds from sale of redeemable convertible preferred stock |
|
47,409,867 |
25,000,000 |
| Proceeds from issuance of common stock warrants |
|
590,132 |
|
| Stock issuance costs |
(4,875,404) |
(1,501,344) |
(208,934) |
| Proceeds from notes payable with detachable common stock warrants |
12,500,000 |
6,934,000 |
95,756 |
| Debt issuance costs |
(449,796) |
|
|
| Payments on notes payable |
(51,481) |
(34,934) |
(15,568) |
| Proceeds from exercise of common stock options |
12,810 |
5,793 |
|
| Net cash provided by financing activities |
56,965,929 |
53,403,514 |
24,871,254 |
| Effect of exchange rates changes on cash |
(10,219) |
(8,115) |
(180,098) |
| Net increase in cash and cash equivalents |
3,925,620 |
25,083,105 |
6,212,051 |
| Cash and cash equivalents |
|
|
|
| Beginning of period |
33,297,970 |
8,214,865 |
2,002,814 |
| End of period |
37,223,590 |
33,297,970 |
8,214,865 |
| Supplemental disclosure of cash flow information |
|
|
|
| Cash paid for interest |
307,944 |
512 |
433 |
| Supplemental disclosure of noncash investing and financing activities |
|
|
|
| Conversion of notes payable and accrued interest into preferred stock |
|
|
10,668,185 |
| Conversion of preferred stock into common stock |
114,527,695 |
|
8,067,307 |
| Preferred stock accretion |
863,226 |
(4,772,991) |
351,371 |
| Interest accrued on long-term debt |
693,114 |
|
|
| Recognition of asset and facility lease obligation related to construction of new property |
$ 3,380,223 |
|
|