Income Taxes (Tables)
12 Months Ended
Dec. 31, 2015
Income taxes  
Schedule of components of loss before income taxes by U.S. and foreign jurisdictions

The components of loss before income taxes by U.S. and foreign jurisdictions are as follows (in thousands):

                                                                                                                                                                                    

 

 

Year ended December 31,

 

 

 

2015

 

2014

 

2013

 

United States

 

$

88,112 

 

$

46,328 

 

$

23,522 

 

Foreign

 

 

1,670 

 

 

1,164 

 

 

1,316 

 

​  

​  

​  

​  

​  

​  

Total

 

$

89,782 

 

$

47,492 

 

$

24,838 

 

​  

​  

​  

​  

​  

​  

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Schedule of reconciliation of the tax expense computed at the statutory federal rate and Company's tax expense

                                                                                                                                                                                    

 

 

Year ended
December 31,

 

 

 

2015

 

2014

 

2013

 

U.S. federal taxes at statutory rate

 

 

34.0

%

 

34.0

%

 

34.0

%

State taxes (net of federal benefit)

 

 

0.8

 

 

0.7

 

 

0.9

 

Non-deductible expenses

 

 

(0.8

)

 

(0.7

)

 

(0.4

)

Foreign tax differential

 

 

(0.2

)

 

(0.8

)

 

(1.8

)

Change in valuation allowance

 

 

(33.8

)

 

(33.2

)

 

(32.7

)

​  

​  

​  

​  

​  

​  

Total

 

 

0.0

%

 

0.0

%

 

0.0

%

 

Schedule of net deferred tax assets

        The tax effects of temporary differences and carryforwards that give rise to significant portions of the deferred tax assets are as follows (in thousands):

                                                                                                                                                                                    

 

 

As of December 31,

 

 

 

2015

 

2014

 

Deferred tax assets:

 

 

 

 

 

 

 

Net operating loss carryforwards

 

$

53,123

 

$

28,022

 

Tax credits

 

 

13

 

 

13

 

Accruals and other

 

 

7,612

 

 

1,914

 

​  

​  

​  

​  

Gross deferred tax assets

 

 

60,748

 

 

29,949

 

Valuation allowance

 

 

(60,304

)

 

(29,498

)

​  

​  

​  

​  

Net deferred tax assets

 

 

444

 

 

451

 

Deferred tax liabilities:

 

 

 

 

 

 

 

Property and equipment

 

$

(444

)

$

(451

)

​  

​  

​  

​  

Total deferred tax liabilities

 

 

(444

)

 

(451

)

​  

​  

​  

​  

Net deferred tax assets

 

$

 

$

 

​  

​  

​  

​  

​  

​  

​  

​  

 

Schedule of reconciliation of gross unrecognized tax benefits

        A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

                                                                                                                                                                                    

 

 

Year ended December 31,

 

 

 

2015

 

2014

 

2013

 

Unrecognized tax benefits, beginning of period

 

$

5,661 

 

$

2,100 

 

$

618 

 

Gross increases—current period tax positions

 

 

2,993 

 

 

1,874 

 

 

1,482 

 

Gross increases—prior period tax positions

 

 

2,775 

 

 

1,687 

 

 

 

​  

​  

​  

​  

​  

​  

Unrecognized tax benefits, end of period

 

$

11,429 

 

$

5,661 

 

$

2,100 

 

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​  

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​