Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Depreciation Useful lives

Depreciation is calculated on a straight-line basis over the estimated useful lives of the respective assets and primarily consists of the following:

Computer equipment and software	3 years
Furniture and fixtures	3-7 years
Leasehold improvements	Shorter of estimated useful life or lease term

Schedule of Computation of Basic and Diluted Net Loss per Share

The following table presents the computation of basic and diluted loss from continuing operations per share (in thousands, except per share amounts):

	2018		2017		2016
Numerator
Net loss from continuing operations	$	(123,716)	$	(126,022)	$	(68,686)
Denominator
Weighted average common shares outstanding, basic and diluted	37,884		27,301		24,785
Loss from continuing operations per share, basic and diluted	$	(3.27)	$	(4.62)	$	(2.77)

Schedule of Potential Common Shares Excluded From Calculation of Diluted Net Loss per Share

The following table presents the potential common shares outstanding that were excluded from the computation of diluted loss from continuing operations per share of common stock for the periods presented because including them would have been antidilutive (in thousands):

	Year Ended December 31,
	2018	2017	2016
Shares subject to outstanding common stock options	3,770	3,865	3,171
Shares subject to outstanding restricted stock units	289	237	85
Shares subject to outstanding warrants to purchase common stock	33	282	1,975
	4,092	4,384	5,231