5. Common Shares

Warrants

Warrant activity is summarized in the following table:


		Weighted		Weighted
		average		average
	Warrants	exercise price		remaining life
	outstanding	per share		(yrs.)	Intrinsic value
As of December 31, 2016	6,514,625	$	1.92	2.6	$	—
As of September 30, 2017	6,514,625	$	1.92	1.9	$	—

Stock-Based Compensation

Under our Stock Option Plan (the “Plan”) and our Long-Term Equity Incentive Plan (the “LTIP”), we may grant options and/or restricted stock units (“RSUs”) or restricted stock awards to our directors, officers, employees and consultants. The combined maximum number of our common shares (“Common Shares”) that may be reserved for issuance under the Plan and the LTIP is a variable number equal to 10% of the issued and outstanding Common Shares on a non-diluted basis at any one time. Options and RSUs under the Plan and LTIP, respectively, are granted from time to time at the discretion of the Board of Directors of the Company (“Board”), with vesting periods and other terms as determined by the Board.

During the year ended December 31, 2016, the Company adopted, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (Accounting Standards Update 2016-09), which included our election to change our accounting policy from estimating forfeiture rates to accounting for forfeitures as they occur. Stock-based compensation expense for the three and nine months ended September 30, 2017 and 2016 is as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Stock options	$	8	$	7	$	32	$	12
Restricted stock units		245		161		648		464
	$	253	$	168	$	680	$	476

As of September 30, 2017, stock options and RSUs had unrecognized compensation expense of $12 and $838, respectively, which is expected to be recognized over a weighted average period of 1.2 and 1.5 years, respectively.

Stock Options

A summary of options under the Plan as of September 30, 2017 is set forth in the following table:


		Weighted average		Weighted average	Aggregate
	Number of	exercise price		remaining	intrinsic
	options	per option		contractual term	value
Outstanding - December 31, 2016	1,544,500	$	1.05	1.8	$	626
Expired	(200,000)		3.14
Outstanding - September 30, 2017	1,344,500	$	0.74	1.2	$	417

Exercisable - September 30, 2017	1,098,250	$	0.82	1.2	$	318

A summary of our unvested stock options as of September 30, 2017 is set forth in the following table:


				Weighted
		Weighted		average
		average		remaining
		grant-date		amortization
	Number of	fair value		period
	options	per option		(Years)
Unvested - December 31, 2016	296,250	$	0.30	1.2
Vested	(50,000)		0.69
Unvested - September 30, 2017	246,250	$	0.22	1.2

Restricted Stock Units

The following table summarizes the RSUs outstanding under the LTIP as of September 30, 2017:


		Weighted average
	Number	grant-date fair
	of units	value per unit
Unvested - December 31, 2016	2,668,387	$	0.49
Cancelled/forfeited	(441,084)		0.34
Vested, net of shares withheld	(1,625,399)		0.38
Granted	966,003		0.79
Unvested - September 30, 2017	1,567,907	$	0.83

A portion of the RSU awards vest on a fixed future date provided the recipient continues to be affiliated with Vista on that date. Other RSU awards vest subject to certain performance and market criteria, including the accomplishment of certain corporate objectives and the Company’s share price performance. The minimum vesting period for RSUs is one year.

During the nine months ended September 30, 2017, the Company withheld shares equivalent to the employee withholding tax obligation which resulted from RSUs vesting in the period. Shares withheld are considered cancelled/forfeited.