STOCK OPTION AND OTHER BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2012

Stock Option Activity

The following table summarizes the Company’s stock option activity:

				Options Outstanding
							Weighted		Weighted
				Number			Average		Average		Aggregate
	Shares			of			Exercise		Contractual		Intrinsic
	Available			Shares			Price		Term (Years)		Value
Balances at December 31, 2009		2,654			4,841			3.49
Increase in authorized shares		3,911
Options granted		(4,841	)		4,841			1.30
Options canceled		2,424			(2,424	)		3.66
Options exercised		—			(330	)		0.87
Balances at December 31, 2010		4,148			6,928			2.02
Increase in authorized shares		2,388
Options granted		(4,925	)		4,925			3.66
Options canceled		1,250			(1,250	)		2.50
Options exercised		—			(859	)		1.90
Balances at December 31, 2011		2,861			9,744			2.80
Increase in authorized shares		300
Options granted		(3,399	)		3,399			3.84
Options canceled		1,416			(1,416	)		3.89
Options exercised		—			(806	)		1.68
Balances at December 31, 2012		1,178			10,921		$	3.07		4.17	$	3,684
Options vested and expected to vest at December 31, 2012					9,429		$	3.03		4.03	$	3,523
Options exercisable at December 31, 2012					4,705		$	2.92		3.33	$	2,517

Option Outstanding Currently Exercisable By Exercise Price

At December 31, 2012, the options outstanding and currently exercisable by exercise price were as follows:

	Options Outstanding						Options Exercisable
			Weighted
			Average
			Remaining		Weighted				Weighted
Range of Exercise Prices	Number Outstanding		Contractual Life (in Years)		Average Exercise Price		Number Exercisable		Average Exercise Price
$0.42 - $ 1.19		1,345		2.82	$	1.03		986	$	1.00
$1.21 - $ 1.23		1,110		3.03		1.22		764		1.22
$1.30 - $ 2.03		1,302		3.66		1.67		691		1.66
$2.16 - $ 2.83		380		5.71		2.30		18		2.45
$2.90 - $ 2.90		1,273		4.78		2.90		376		2.90
$2.98 - $ 3.29		1,130		5.69		3.28		31		3.17
$3.39 - $ 3.78		1,098		4.05		3.72		497		3.71
$3.88 - $ 4.30		1,209		4.95		4.25		132		4.06
$4.35 - $ 4.66		1,123		4.41		4.53		465		4.52
$4.72 - $ 11.88		951		3.73		6.33		745		6.67
$0.42 - $ 11.88		10,921		4.17	$	3.07		4,705	$	2.92

Schedule of Assumptions Used In Black-Scholes Valuation Model and Weighted Average Assumptions

The Company recognizes stock-based compensation expense in accordance with ASC 718, and has estimated the fair value of each option award on the grant date using the Black-Scholes option valuation model and the weighted average assumptions noted in the following table.

	Year Ended December 31,
	2012			2011			2010
Dividend yield		—	%		—	%		—	%
Risk-free interest rate		0.60	%		1.06	%		1.15	%
Expected term (years)		4.00			4.02			3.12
Expected volatility		65	%		65	%		77	%

Stock-Based Compensation Expense

The following table summarizes the consolidated stock-based compensation expense by line items in the consolidated statement of operations:

	Year Ended December 31,
	2012		2011		2010
Research and development	$	3,491	$	1,387	$	480
Sales and marketing		386		351		217
General and administrative		1,945		1,372		871
Total stock-based compensation expense	$	5,822	$	3,110	$	1,568