Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Estimated Weighted Average Grant Date Fair Value per Share

The Company granted options and awards for 1,160,535 and 5,833 shares of common stock in the years ended December 31, 2013 and 2012, respectively. The fair values of the majority of employee stock options granted in the years ended December 31, 2013 and 2012 were estimated at the date of grant using the Black-Scholes model with the following assumptions and had the following estimated weighted average grant date fair value per share:

	Years Ended December 31,
	2013			2012
Expected term		5.8 years			5.3 years
Expected volatility		96	%		108	%
Risk-free interest rate		1.62	%		0.15	%
Expected dividend yield		0	%		0	%
Weighted-average grant date fair value per share	$	1.05		$	4.68

Summary of Stock Option Activities

A summary of ARCA’s stock option activities for the years ended December 31, 2013 and 2012, and related information as of December 31, 2013, is as follows:

	For the years ended December 31,
	2013					2012
	Number of Options			Weighted Average Exercise Price		Number of Options			Weighted Average Exercise Price
Options outstanding, beginning of period		144,019		$	18.28		144,039		$	19.20
Granted		741,535			1.38		5,833			6.00
Exercised		—			—		—			—
Forfeited and cancelled		(42,112	)		11.62		(5,853	)		27.96
Options outstanding, end of period		843,442		$	3.76		144,019		$	18.28
Options exercisable, end of period		194,550		$	11.14		125,666		$	18.77
Options vested and expected to vest		832,941		$	3.78

Summary of Stock Options Outstanding and Exercisable

The following table summarizes information about stock options outstanding and exercisable as of December 31, 2013:

					Options Outstanding						Options Exercisable
Range of Exercise Prices					Number Outstanding		Weighted Average Remaining Contractual Term (in years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$	0.36	—	$	1.33		1,433		8.56	$	1.21		286	$	0.71
	1.38	—		1.38		727,869		9.46		1.38		98,233		1.38
	1.40	—		22.98		96,465		5.85		12.04		78,356		13.18
	22.98	—		33.42		17,168		4.42		32.78		17,168		32.78
	33.42	—		440.40		250		0.33		263.94		250		263.94
	440.40	—		1,908.00		257		0.30		1,443.56		257		1,443.56
						843,442		8.94	$	3.76		194,550	$	11.14

Summary of RSU activity

A summary of RSU activity for the year ended December 31, 2013 is presented below:

Restricted Stock Awards	Number of Shares	Weighted- Average Grant Date Fair Value
Unvested RSUs at December 31, 2012	—	$	—
Granted	419,000		1.39
Vested	—		—
Forfeited and cancelled	—		—
Unvested RSUs at December 31, 2013	419,000	$	1.39

Non-Cash, Share-Based Compensation Expense

For the years ended December 31, 2013 and 2012 and for the period from Inception through December 31, 2013, the Company recognized the following non-cash, share-based compensation expense (in thousands):

	Years Ended December 31,				Period from December 17, 2001 (date of inception) to December 31,
	2013		2012		2013
Research and Development	$	77	$	94	$	667
Selling, General and Administrative		206		212		1,817
Restructuring Expense		—		—		387
Total	$	283	$	306	$	2,871