| Schedule of Deferred Tax Assets |
The components of our deferred tax assets are summarized as follows:
|
|
|
As of December 31,
|
|
|
|
|
2015
|
|
|
2014
|
|
|
Deferred tax assets:
|
|
|
|
|
|
|
|
|
|
Net operating loss carryforwards
|
|
$
|
60,129,827
|
|
|
$
|
50,117,798
|
|
|
R&D credit carryforwards
|
|
|
9,465,900
|
|
|
|
8,394,408
|
|
|
Stock compensation
|
|
|
1,898,394
|
|
|
|
1,849,847
|
|
|
Intangibles
|
|
|
1,921,934
|
|
|
|
1,931,193
|
|
|
Temporary differences
|
|
|
801,002
|
|
|
|
910,354
|
|
|
Deferred tax assets before valuation allowance
|
|
|
74,217,057
|
|
|
|
63,203,600
|
|
|
Valuation allowance
|
|
|
(74,217,057
|
)
|
|
|
(63,203,600
|
)
|
|
Net deferred tax assets
|
|
$
|
—
|
|
|
$
|
—
|
|
|
| Schedule of NOL and Credit Carryforward Amounts |
The details of our U.S. net operating loss and federal R&D credit carryforward amounts and expiration dates are summarized as follows:
|
|
|
|
|
As of December 31, 2015
|
|
|
Generated
|
|
Expiration
|
|
U.S. Net
Operating
Loss
Carryforwards
|
|
|
U.S. R&D
Credit
Carryforwards
|
|
|
1998
|
|
2018
|
|
$
|
17,142,781
|
|
|
$
|
1,173,387
|
|
|
1999
|
|
2019
|
|
|
—
|
|
|
|
130,359
|
|
|
2000
|
|
2020
|
|
|
—
|
|
|
|
71,713
|
|
|
2001
|
|
2021
|
|
|
—
|
|
|
|
39,128
|
|
|
2002
|
|
2022
|
|
|
1,282,447
|
|
|
|
5,350
|
|
|
2003
|
|
2023
|
|
|
337,714
|
|
|
|
2,905
|
|
|
2004
|
|
2024
|
|
|
1,237,146
|
|
|
|
22,861
|
|
|
2005
|
|
2025
|
|
|
2,999,083
|
|
|
|
218,332
|
|
|
2006
|
|
2026
|
|
|
3,049,735
|
|
|
|
365,541
|
|
|
2007
|
|
2027
|
|
|
2,842,078
|
|
|
|
342,898
|
|
|
2008
|
|
2028
|
|
|
2,777,503
|
|
|
|
531,539
|
|
|
2009
|
|
2029
|
|
|
13,727,950
|
|
|
|
596,843
|
|
|
2010
|
|
2030
|
|
|
5,397,680
|
|
|
|
1,094,449
|
|
|
2011
|
|
2031
|
|
|
1,875,665
|
|
|
|
1,950,744
|
|
|
2012
|
|
2032
|
|
|
28,406,659
|
|
|
|
468,008
|
|
|
2013
|
|
2033
|
|
|
37,450,522
|
|
|
|
374,406
|
|
|
2014
|
|
2034
|
|
|
34,088,874
|
|
|
|
648,252
|
|
|
2015
|
|
2035
|
|
|
24,971,225
|
|
|
|
1,087,317
|
|
|
Total carryforwards
|
|
$
|
177,587,062
|
|
|
$
|
9,124,032
|
|
|
| Schedule of Effective Income Tax Rate Reconciliation |
Reconciliations between the statutory federal income tax rate and our effective tax rate for continuing operations are as follows:
|
|
|
Years Ended December 31,
|
|
|
|
|
2015
|
|
|
2014
|
|
|
2013
|
|
|
|
|
Amount
|
|
|
%
|
|
|
Amount
|
|
|
%
|
|
|
Amount
|
|
|
%
|
|
|
Benefit at statutory rate
|
|
$
|
(9,777,786
|
)
|
|
|
(34.0
|
)%
|
|
$
|
(12,147,068
|
)
|
|
|
(34.0
|
)%
|
|
$
|
(14,517,816
|
)
|
|
|
(34.0
|
)%
|
|
Adjustments to valuation allowance
|
|
|
9,728,667
|
|
|
|
33.8
|
%
|
|
|
12,925,380
|
|
|
|
36.2
|
%
|
|
|
15,399,021
|
|
|
|
36.1
|
%
|
|
Adjustments to R&D credit
carryforwards
|
|
|
(612,087
|
)
|
|
|
(2.1
|
)%
|
|
|
(340,886
|
)
|
|
|
(1.0
|
)%
|
|
|
(842,414
|
)
|
|
|
(2.0
|
)%
|
|
Disqualified debt interest
|
|
|
438,007
|
|
|
|
1.5
|
%
|
|
|
—
|
|
|
|
0.0
|
%
|
|
|
—
|
|
|
|
0.0
|
%
|
|
Permanent items and other
|
|
|
(212,852
|
)
|
|
|
(0.7
|
)%
|
|
|
(437,426
|
)
|
|
|
(1.2
|
)%
|
|
|
(38,791
|
)
|
|
|
(0.1
|
)%
|
|
Benefit per financial statements
|
|
$
|
(436,051
|
)
|
|
|
|
|
|
$
|
—
|
|
|
|
|
|
|
$
|
—
|
|
|
|
|
|
|