Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of assumptions used in estimation of fair value of the share-based payment awards on the grant date

The fair value of the Company’s stock options granted during the three months ended March 31, 2019 and 2018 was estimated on the grant dates using the Black-Scholes valuation option-pricing model with the following assumptions:


	Three Months Ended March 31,
	2019			2018
Risk-free interest rate		2.5	%		2.2	%
Volatility		128.4	%		109.5	%
Expected life (years)		3 - 5			4.0
Dividend yield		—	%		—	%

Summary of option and RSU activity under Amended and Restated 2000 Stock Option and Equity Incentive Plan and Amended and Restated 2010 Equity Incentive Plan

A summary of option and RSU activity under the Company’s Amended and Restated 2010 Equity Incentive Plan (the Plan) is presented below (in thousands, except exercise price):


				Options outstanding
	Shares Available for Grant			Number of Shares			Weighted Average Exercise Prices
Balance at January 1, 2019		4,007			337		$	4.19
Additional shares authorized under the Plan		50			—			—
RSUs granted		(2,028	)		—			—
RSUs cancelled and returned to the Plan		11			—			—
Options granted		(1,297	)		1,297		$	0.20
Options cancelled and returned to the Plan		1			(1	)	$	7.20

Balance at March 31, 2019		744			1,633		$	1.02

Summary of RSU activity under the Plan

A summary of RSU activity under the Plan is presented below (in thousands, except for fair value):


	Number of Shares			Weighted Average Grant-Date Fair Value
Non-vested shares at December 31, 2018		272		$	1.23
Granted		2,028		$	0.20
Vested		(167	)	$	1.48
Cancelled		(11	)	$	1.26

Non-vested shares at March 31, 2019		2,122		$	0.23

Summary of significant ranges of outstanding and exercisable options

The following table summarizes significant ranges of outstanding and exercisable options as of March 31, 2019 (in thousands, except contractual life and exercise price):


	Options Outstanding						Options Exercisable
Range of Exercise Price	Number Outstanding		Weighted Average Remaining Contractual Life (in Years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price		Aggregate Intrinsic value
$0.18 - $0.74		1,297		2.80	$	0.20		30	$	0.20	$	—
$0.75 - $1.27		160		4.55	$	0.75		53	$	0.75	$	—
$1.28 - $7.19		51		5.15	$	2.09		23	$	2.93	$	—
$7.20 - $20.49		106		7.04	$	7.20		92	$	7.20	$	—
$20.50 - $46.20		19		5.94	$	21.53		19	$	21.53	$	—

$0.18 - $46.20		1,633		5.52	$	1.02		217	$	5.46	$	—