Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Summary of Assumptions Used to Compute Share-Based Compensation Costs for Stock Options Granted

The assumptions used to compute the share-based compensation costs for the stock options granted during the years ended December 31, 2013, 2012 and 2011 are as follows:



	Year Ended December 31,
	2013	2012	2011
Risk-free interest rate	1.1-1.8%	0.9-1.2%	1.2-2.5%
Expected dividend yield	—	—	—
Weighted average expected life (years)	5.3-5.5	5.3-5.8	5.8-5.9
Volatility	75-76%	75-78%	56-57%

Summary of Compensation Cost for Stock-Based Compensation Arrangements

The compensation cost that has been included in the Company’s consolidated statement of operations for all stock-based compensation arrangements is detailed as follows (in thousands, except per share amounts):



	Year Ended December 31,
	2013		2012		2011
Cost of revenues	$	228	$	137	$	180
Research and development	719		261		289
Sales and marketing	459		1,695		693
General and administrative	2,672		1,447		1,263
Total	$	4,078	$	3,540	$	2,425

Weighted Average Number of Common Shares Outstanding

For purposes of this calculation, common stock subject to repurchase by the Company and options are considered to be common stock equivalents and are only included in the calculation of diluted earnings per share when their effect is dilutive. (In thousands, except per share data):



	Year Ended December 31,
	2013			2012			2011
Numerator:
Net loss	$	(82,227	)	$	(15,459	)	$	(22,181	)
Denominator:
Weighted average common shares outstanding	97,111			90,870			89,165
Weighted average unvested common shares subject to repurchase	(876		)	(652		)	(368		)
Weighted average common shares outstanding—basic	96,235			90,218			88,797
Effect of dilutive securities:
Options, warrants and restricted share awards	—			—			—
Weighted average common shares outstanding—diluted	96,235			90,218			88,797
Net loss per common share:
Basic and diluted net loss per share	$	(0.85	)	$	(0.17	)	$	(0.25	)

Weighted-Average Anti-Dilutive Securities Not Included in Diluted Net Loss Per Share

The weighted-average anti-dilutive securities not included in diluted net loss per share were as follows (in thousands):



	Year Ended December 31,
	2013	2012	2011
Options to purchase common stock	4,597	4,621	4,323
Warrants to purchase common stock	594	594	94
Unvested restricted stock awards	807	877	368
	5,998	6,092	4,785