Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Assumptions used in Estimation of Fair Value of the Share-based Payment Awards on the Grant Date

	Year Ended
	December 31,
	2020	2019
Risk-free interest rate	1.6% - 2.5%	1.6% - 2.5%
Volatility	128% - 138.5%	128% - 138.5%
Expected life (years)	3.0 - 5.0	3.0 - 5.0
Dividend yield	0 %	0 %

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 stock option and restricted stock unit (RSU) award activity under the Plans is presented below (in thousands, except exercise price):

				Options outstanding
							Weighted
	Shares						Average
	Available			Number of			Exercise
	for Grant			Shares			Prices
Balance as of January 1, 2019		200			17		$	96.24
Additional shares authorized under the Plan		183			—			—
RSUs granted		(120	)		—			—
RSUs cancelled and returned to the Plan		1			—			—
Options granted		(145	)		145		$	2.64
Options cancelled and returned to the Plan		1			(1	)	$	144.00
Plan termination		(32	)		—		$	—
Balance as of December 31, 2019		88			161		$	10.85
RSUs granted		(9	)		—			—
RSUs cancelled and returned to the Plan		2			—			—
Options cancelled		—			(2	)	$	4.00
Balance as of December 31, 2020		81			159		$	10.82

Summary of RSU Activity under the Plans

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

				Weighted
				Average
	Number of			Grant-Date
	Shares			Fair Value
Non-vested shares as of January 1, 2019		14		$	24.31
Granted		120		$	3.79
Vested		(30	)	$	12.89
Cancelled		(1	)	$	25.13
Non-vested shares as of December 31, 2019		103		$	3.75
Granted		9		$	1.74
Vested		(43	)	$	3.72
Cancelled		(4	)	$	4.00
Non-vested shares as of December 31, 2020		65		$	3.48

Summary of Significant Ranges of Outstanding and Exercisable Options

The following table summarizes significant ranges of outstanding and exercisable options at December 31, 2020 (in thousands, except contractual life and exercise price):

	Options Outstanding						Options Exercisable
			Weighted
			Average
			Remaining		Weighted				Weighted
			Contractual		Average				Average		Aggregate
	Number		Life		Exercise		Number		Exercise		Intrinsic
Range of Exercise Price	Outstanding		(in Years)		Price		Exercisable		Price		value
$1.57 - $14.99		143		8.26	$	2.62		68	$	2.94	$	25
$15.00 - $25.59		8		2.74	$	15.00		8	$	15.00	$	—
$25.60 - $143.99		2		3.35	$	41.81		2	$	41.81	$	—
$144.00 - $409.99		5		5.65	$	144.00		5	$	144.00	$	—
$410.00 - $924.00		1		4.19	$	430.64		1	$	430.64	$	—
$1.57 - $924.00		159		7.80	$	10.82		84	$	18.39	$	25