Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Stock-Based Compensation

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

	Year Ended December 31,
	2017	2016	2015
Risk-free interest rate	1.6% - 1.8%	1% - 2.1%	0.6%  -1.7%
Volatility	70.2% - 101.5%	61.4% - 65.0%	55.7% - 59.3%
Expected life (years)	4.0	3.0 - 5.0	3.0 - 5.0
Dividend yield	0%	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):

		Awards outstanding
			Weighted
	Shares		Average
	Available	Number of	Exercise
	for Grant	Shares	Prices
Balance at January 1, 2015	176	599	$	38.70
Additional shares authorized under the Plan	50	—		—
RSUs cancelled and returned to the Plan	2	—		—
Options granted	(154)	154	$	20.20
Options cancelled and returned to the Plan	70	(70)	$	35.20
Options exercised	—	(8)	$	(16.40)
Options expired	(38)	—	$	32.00
Balance at December 31, 2015	106	675	$	35.10
Additional shares authorized under the Amended 2010 Plan	50	—		—
RSUs granted	(144)	—		—
RSUs cancelled and returned to Plan	7	—		—
Options granted	(384)	384	$	6.96
Options cancelled and returned to Plan	479	(479)	$	35.64
Options cancelled and expired	—	(58)	$	44.80
Balance at December 31, 2016	114	522	$	13.88
Additional shares authorized under the Amended 2010 Plan	250	—		—
RSUs granted	(407)	—		—
RSUs cancelled and returned to Plan	59	—		—
Options granted	(160)	160	$	0.76
Options cancelled and returned to Plan	375	(375)	$	15.69
Balance at December 31, 2017	231	307	$	4.81

Summary of RSU activity under the Plans

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

		Weighted
		Average
	Number of	Grant-Date
	Shares	Fair Value
Non-vested shares at January 1, 2015	39	$	46.11
Granted	—	$	—
Vested	(13)	$	45.97
Cancelled	(2)	$	46.20
Non-vested shares at December 31, 2015	24	$	47.17
Granted	144	$	5.30
Vested	(12)	$	46.06
Cancelled	(8)	$	15.67
Non-vested shares at December 31, 2016	148	$	8.13
Granted	407	$	0.93
Vested	(120)	$	5.76
Cancelled	(59)	$	5.04
Non-vested shares at December 31, 2017	376	$	1.58

Summary of significant ranges of outstanding and exercisable options

The following table summarizes significant ranges of outstanding and exercisable options as of December 31, 2017 (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
$0.75 - $2.35	160	5.80	$	0.75	—	$	—	$	58
$2.36 - $7.19	11	8.66	$	4.92	6	$	5.18	$	—
$7.20 - $20.49	114	8.64	$	7.20	51	$	7.20	$	—
$20.50 - $43.59	20	6.83	$	20.89	15	$	21.02	$	—
$44.60 - $46.19	1	2.76	$	44.60	1	$	44.60	$	—
$46.20 - $46.20	1	6.13	$	46.20	—	$	46.20	$	—
$0.75 - $46.20	307	7.02	$	4.81	73	$	10.55	$	58
Vested and expected to vest	281	7.09	$	5.07				$	50
Exercisable	73	8.15	$	10.55				$	—