Convertible Preferred Stock and Stockholders' Deficit (Tables)

9 Months Ended

Sep. 30, 2012

Convertible Preferred Stock Balances

As of December 31, 2010 and 2011, convertible preferred stock balances were as follows:

	Shares Authorized		Shares Issued and Outstanding		Carrying Value		Liquidation Amount
(in thousands, except share information)
Series A		1,527,611		428,922	$	1,835	$	2,200
Series B-1		3,425,152		961,720		4,726		4,932
Series B-2		14,811,323		4,119,759		21,039		21,128
Series C		6,944,450		1,949,874		19,905		20,000
Series D		12,400,000		3,196,755		35,673		37,002
		39,108,536		10,657,030	$	83,178	$	85,262

In May and June 2012, the Company issued 1,672,300 shares of Series E Preferred at a price of $12.11 per share, for gross proceeds of $20.2 million. As of September 30, 2012, convertible preferred stock balances were as follows:

	Shares Authorized		Shares Issued and Outstanding		Carrying Value		Liquidation Amount
(in thousands, except share information)	(unaudited)
Series A		1,527,611		428,922	$	1,835	$	2,200
Series B-1		3,425,152		961,720		4,726		4,932
Series B-2		14,811,323		4,119,759		21,039		21,128
Series C		6,944,450		1,949,874		19,905		20,000
Series D		11,385,196		3,196,755		35,673		37,002
Series E		22,058,823		1,672,300		18,845		20,250
		60,152,555		12,329,330	$	102,023	$	105,512

Shares of Common Stock Reserved for Issuance

The Company had reserved the following shares of common stock for issuance:

	December  31, 2011		September  30, 2012
			(unaudited)
Conversion of Series A Preferred		428,922		428,922
Conversion of Series B-1 Preferred		961,720		961,720
Conversion of Series B-2 Preferred		4,119,759		4,119,759
Exercise and conversion of Series B-2 Preferred and Series E Preferred warrants		38,997		55,513
Conversion of Series C Preferred		1,949,874		1,949,874
Conversion of Series D Preferred		3,196,755		3,196,755
Conversion of Series E Preferred		—		6,193,741
Common stock available for grant of stock awards		1,011,650		2,122,035
Common stock options outstanding		1,086,299		1,057,468
		12,793,976		20,085,787

Activity Under 2012 Plan

Activity under the Company’s stock plans is as follows:

	Shares Available for Grant			Number of Options Issued and Outstanding			Weighted-Average Exercise Price
Balances at December 31, 2008		911,337			755,566		$	1.21
Stock awards granted		(105,574	)		—
Options granted		(371,899	)		371,899			1.21
Options canceled		77,168			(77,168	)		1.03
Options exercised		—			(9,639	)		0.71
Stock awards forfeited		11,465			—
Balances at December 31, 2009		522,497			1,040,658			1.00
Stock awards granted		(134,530	)		—
Options granted		(145,375	)		145,375			1.46
Options canceled		76,098			(76,098	)		1.07
Options exercised		—			(147,154	)		0.82
Balances at December 31, 2010		318,690			962,781			1.07
Additional shares authorized		912,544			—
Stock awards granted		(72,441	)		—
Options granted		(324,585	)		324,585			1.46
Options canceled		165,980			(165,980	)		1.25
Options exercised		—			(35,087	)		0.96
Stock awards cancelled and forfeited		11,462			—
Balances at December 31, 2011		1,011,650			1,086,299			1.18
Additional shares authorized (unaudited)		1,123,131			—
Options granted (unaudited)		(416,541	)		416,541			4.31
Options canceled (unaudited)		386,888			(386,888	)		1.25
Options exercised (unaudited)		—			(58,484	)		0.96
Stock awards cancelled and forfeited (unaudited)		16,907			—
Balances at September 30, 2012 (unaudited)		2,122,035			1,057,468			2.39
Options vested and expected to vest at December 31, 2011					1,032,033			1.18
Options vested and expected to vest at September 30, 2012 (unaudited)					1,004,642			2.39

Additional Information Regarding Options Outstanding

Additional information regarding options outstanding as of December 31, 2011 is as follows:

	Options Outstanding and Exercisable
Exercise Price	Number of Shares Outstanding		Weighted- Average Remaining Contractual Life (In Years)
$0.50		44,542		3.29
0.54		61,070		5.02
0.89		87,791		5.56
1.03		250,207		6.34
1.07		4,678		0.80
1.21		260,090		7.14
1.46		377,921		9.05
		1,086,299

Additional information regarding options outstanding as of September 30, 2012 is as follows:

	Options Outstanding and Exercisable
Exercise Price	Number of Shares Outstanding		Weighted- Average Remaining Contractual Life (In Years)
	(unaudited)
$0.50		37,242		2.53
0.54		45,627		4.27
0.89		15,723		4.80
1.03		182,761		5.56
1.21		177,394		6.39
1.46		182,742		8.18
2.17		66,405		9.45
4.74		349,574		9.83
		1,057,468

Employee And Director Stock Options Granted under 2001 Plan, Assumption Used In Black-Scholes Model

The fair value-based measurement of employee and director stock options granted under the Company’s stock plans was estimated at the date of grant using the Black-Scholes model with the following assumptions:

	Year Ended December 31,									Nine Months Ended September 30,
	2009			2010			2011			2011			2012
										(unaudited)
Expected term		6 years			6 years			6 years			6 years			6 years
Expected volatility		75-84	%		87-88	%		58-60	%		58-60	%		57-59	%
Risk-free interest rate		1.9-2.9	%		1.5-2.9	%		1.9-2.7	%		1.9-2.7	%		0.8-1.4	%
Expected dividend yield		0	%		0	%		0	%		0	%		0	%

Recent Grant Dates And Related Exercise Prices Of Stock Options Granted to Employees And Directors

Recent grant dates and the related exercise prices of stock options granted to employees and directors from January 1, 2011 through September 30, 2012 were as follows:

	Number of Shares Subject to Options Granted		Exercise Price		Fair Value Estimate per Common Share
January 26, 2011		92,939	$	1.46	$	0.82
April 5, 2011		140,391		1.46		0.82
July 19, 2011		91,255		1.46		0.82
March 12, 2012 (unaudited)		66,967		2.17		1.18
July 31, 2012 (unaudited)		349,574		4.74		8.16

Restricted Stock Awards, granted

The Company also granted restricted stock awards during the period from January 1, 2011 through September 30, 2012 as summarized below:

	Number of Shares Subject to Awards Granted		Fair Value Estimate per Common Share
January 26, 2011		72,441	$	1.46

Total Employee And Director Stock-Based Compensation Expense

Total employee and director stock-based compensation expense recognized was as follows:

	Years Ended December 31,						Nine Months Ended September 30,
(In thousands)	2009		2010		2011		2011		2012
							(unaudited)
General and administrative	$	170	$	152	$	93	$	69	$	303
Research and development		175		147		128		97		313
	$	345	$	299	$	221	$	166	$	616