| Income Tax Disclosure [Abstract] | Period [Axis] |
|---|
2016-01-01 - 2016-12-31 |
|---|
Income Tax Disclosure [Abstract] | |
Income (Loss) before Income Taxes |
Income (loss) before income taxes consisted of the following:
|
|
|
Years Ended December 31, |
|
|
|
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
|
|
(in thousands) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Domestic |
|
$ |
(156,409 |
) |
|
$ |
(85,595 |
) |
|
$ |
8,826 |
|
|
Foreign |
|
|
155 |
|
|
|
125 |
|
|
|
82 |
|
|
Income (loss) before income taxes |
|
$ |
(156,254 |
) |
|
$ |
(85,470 |
) |
|
$ |
8,908 |
|
|
Effective Income Tax Rate Reconciliation |
The effective income tax rate of the Company’s provision for income taxes differed from the federal statutory rate of 34% as follows:
|
|
|
Years Ended December 31, |
|
|
|
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Federal statutory income tax rate |
|
|
34.0 |
% |
|
|
34.0 |
% |
|
|
34.0 |
% |
|
Stock-based compensation |
|
|
(1.0 |
%) |
|
|
(1.0 |
%) |
|
|
0.9 |
% |
|
Research and development credits |
|
|
2.4 |
% |
|
|
2.4 |
% |
|
|
(13.6 |
%) |
|
Other |
|
|
(0.1 |
%) |
|
|
(0.1 |
%) |
|
|
0.9 |
% |
|
Change in valuation allowance |
|
|
(35.3 |
%) |
|
|
(35.3 |
%) |
|
|
(22.2 |
%) |
|
Effective tax rate |
|
|
0.0 |
% |
|
|
0.0 |
% |
|
|
0.0 |
% |
|
Deferred Income Tax Assets and Liabilities |
The Company’s net deferred income tax assets and liabilities are as follows:
|
|
|
December 31, |
|
|
|
|
2016 |
|
|
2015 |
|
|
|
|
(in thousands) |
|
|
|
|
|
|
|
|
|
|
|
|
Deferred income tax assets: |
|
|
|
|
|
|
|
|
|
Net operating loss carryforwards |
|
$ |
119,810 |
|
|
$ |
71,805 |
|
|
Research and development credits |
|
|
11,540 |
|
|
|
7,910 |
|
|
Other |
|
|
5,443 |
|
|
|
1,961 |
|
|
Total deferred income tax assets |
|
|
136,793 |
|
|
|
81,676 |
|
|
Less: Valuation allowance |
|
|
(136,793 |
) |
|
|
(81,676 |
) |
|
Net deferred income tax assets |
|
$ |
— |
|
|
$ |
— |
|
|
Summary of Changes in Deferred Tax Valuation Allowance |
The table below summarizes changes in the deferred tax valuation allowance:
|
|
|
Balance at Beginning of Year |
|
|
Charged to Costs and Expenses |
|
|
Write-offs |
|
|
Balance at End of Year |
|
|
|
|
(in thousands) |
|
|
Deferred income tax valuation allowance: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
For year ended December 31, 2014 |
|
|
53,428 |
|
|
|
(1,978 |
) |
|
|
— |
|
|
|
51,450 |
|
|
For year ended December 31, 2015 |
|
|
51,450 |
|
|
|
30,226 |
|
|
|
— |
|
|
|
81,676 |
|
|
For year ended December 31, 2016 |
|
|
81,676 |
|
|
|
55,117 |
|
|
|
— |
|
|
|
136,793 |
|
|
Unrecognized Tax Benefits |
The total balance of unrecognized gross tax benefits was as follows:
|
|
|
|
|
Years Ended December 31, |
|
|
|
|
|
|
2016 |
|
|
2015 |
|
|
2014 |
|
|
|
|
|
|
(in thousands) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Unrecognized tax benefits at beginning of year |
|
|
|
$ |
952 |
|
|
$ |
592 |
|
|
$ |
383 |
|
|
Additions based on tax positions taken in prior years |
|
|
|
|
35 |
|
|
|
— |
|
|
|
43 |
|
|
Additions based on tax positions taken in the current year |
|
|
|
|
606 |
|
|
|
360 |
|
|
|
166 |
|
|
Unrecognized tax benefits at end of year |
|
|
|
$ |
1,593 |
|
|
$ |
952 |
|
|
$ |
592 |
|
|