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Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity [Line Items]

Summary Of Stock Option Activity



			Stock Options Outstanding
	Shares available		Number					Weighted average
	for grant		of shares		Exercise price			exercise price
Balances, December 31, 2016	6,471		22,501		$	1.16 – 16.00		$	6.30
Additional shares reserved	4,634
Options granted	(6,239)		6,239		$	2.66 – 5.37		$	4.84
Options exercised	—		(1,407)		$	1.16 – 5.27		$	2.55
Options canceled	1,929		(1,929)		$	1.16 – 16.00		$	7.00
Balances, December 31, 2017	6,795		25,404		$	1.16 – 16.00		$	6.10

Reconciliation Of Outstanding And Exercisable Stock Options



	Options Outstanding							Options Exercisable
			Weighted average
	Number		remaining contractual		Weighted average			Number		Weighted average
	outstanding		life (Years)		exercise price			vested		exercise price
	25,404,152		6.51		$	6.10		16,802,740		$	6.05

Schedule Of Stock-Based Compensation Expense



	Years Ended December 31,
	2017			2016			2015
Cost of revenue	$	2,311		$	2,133		$	1,313
Research and development		8,506			8,257			5,196
Sales, general and administrative		9,535			9,172			7,331
Total stock-based compensation expense	$	20,352		$	19,562		$	13,840

Stock Options [Member]

Stockholders' Equity [Line Items]

Schedule Of Fair Value Of Employee Stock Options



		Years Ended December 31,
		2017			2016			2015
Expected term (years)			6.1 years			6.1 years			6.1 years
Expected volatility			70.0%			70.0%			70.0%
Risk-free interest rate			2.1%			1.5%			1.7%
Dividend yield			—			—			—

ESPP [Member]

Stockholders' Equity [Line Items]

Schedule Of Fair Value Of Employee Stock Options



		Years Ended December 31,
		2017			2016			2015
Expected term (years)			0.5 - 2.0			0.5 - 2.0			0.5 - 2.0
Expected volatility			70.0%			70.0%			70.0%
Risk-free interest rate			0.8%-1.4%			0.5%-0.9%			0.1%-0.7%
Dividend yield			—			—			—