6. Common Shares

Share Issuances

During the years ended December 31, 2018 and 2017 we issued 856,154 and 1,625,399 common shares, respectively, in connection with the vesting of RSUs and/or stock option exercises.

Warrants

Outstanding warrants are 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 December 31, 2017	6,514,625	$	1.92	1.6	$	—
As of December 31, 2018	6,514,625	$	1.92	0.6	$	—

Stock-Based Compensation

Under the Company’s stock option plan (the “Plan”), we may grant options to purchase common shares of the Company (“Common Shares”) to our directors, officers, employees and consultants. The maximum number of our Common Shares that may be reserved for issuance under the Plan, together with RSUs currently outstanding under the Long-Term Incentive Plan (“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 under the Plan are granted from time to time at the discretion of the Board, with vesting periods and other terms as determined by the Board. Stock-based compensation expense for the years ended December 31, 2018 and 2017 is as follows:


		Year Ended December 31,
	2018		2017
Stock options	$	320	$	36
Restricted stock units		662		838
	$	982	$	874

Phantom units		23		—

As of December 31, 2018, stock options, RSUs, and phantom units had unrecognized compensation expense of $159, $210, and $117 respectively, which is expected to be recognized over a weighted average period of 1.1, 0.7, and 1.5 years, respectively.

Stock Options

A summary of option activity under the Plan as of December 31, 2018 and 2017 and changes during the period then ended 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	1.79	$	626
Expired	(400,000)		2.87			—
Outstanding - December 31, 2017	1,144,500	$	0.42	1.15	$	346
Granted	1,142,000		0.71
Exercised	(218,600)		0.39			36
Cancelled/Forfeited	(748,751)		0.36
Outstanding - December 31, 2018	1,319,149	$	0.71	3.84	$	1

Exercisable - December 31, 2018	559,480	$	0.70	3.23	$	1

A summary of our unvested stock options as of December 31, 2018 and 2017 and changes during the period then ended 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		0.49	1.23
Vested	(50,000)		0.69
Unvested - December 31, 2017	246,250	$	0.22	0.99
Granted	1,142,000		0.45
Cancelled/Forfeited	(246,250)		0.22
Vested	(382,331)		0.45
Unvested - December 31, 2018	759,669	$	0.45	1.14

No stock options were granted for the year ended December 31, 2017. The fair value of stock options granted during the year ended December 31, 2018 to employees, directors and consultants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions:



	2018
Expected volatility	76.2	%
Risk-free interest rate	2.7	%
Expected life (years)	5
Dividend yield	0	%
Forfeiture assumption	—	%

Option pricing models require the input of highly subjective assumptions, including the expected price volatility. Expected price volatility is based on the historical volatility of our common shares. Changes in the subjective input assumptions can materially affect the fair value estimate. The expected term of the options granted represents the period of time that the options granted are expected to be outstanding. The risk-free rate for the periods within the contractual term of the option is based on the U.S. Treasury yield curve in effect at the date of grant.

Option Amendment

In July 2018, the Company amended certain 2013 stock option agreements, expiring December 30, 2018 subject to the potential for a temporary extension under the terms of the Plan, for seven executives and directors (the “Option Amendment”). The amendment provides each grantee the opportunity to receive a cash buyout of certain vested, unexercised 2013 options in lieu of exercising the option to purchase shares. This cash buyout is based on the intrinsic value of each option at the time of the buyout as determined by the Company’s Compensation Committee prior to the buyout. As a result of this modification, the Company accounted for these options as awards classified as liabilities. The options were previously accounted for as awards classified as equity. The Company recognized no additional compensation expense in the year ended December 31, 2018. In December 2018, all options under the Option Amendment were settled with cash buyouts totaling $61 and the related options were cancelled.

Restricted Stock Units

The following table summarizes the RSU activity under the LTIP as of December 31, 2018 and 2017 and changes during the years then ended:


		Weighted average
	Number	grant-date fair
	of RSUs	value per RSU
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		0.82
Unvested - December 31, 2017	1,567,907	$	0.85
Cancelled/forfeited	(246,683)		0.90
Vested, net of shares withheld	(637,554)		0.88
Granted	319,000		0.75
Unvested - December 31, 2018	1,002,670	$	0.78

During the years ended December 31, 2018 and 2017, the Company withheld shares equivalent to the value of employee withholding tax obligations which resulted from RSUs vesting in the period. Shares withheld are considered cancelled/forfeited.

Under the LTIP, 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. Of the unvested RSUs, approximately 26% could vest based on a fixed future date, approximately 29% and 45% could vest on performance and market criteria respectively. The vesting period for all RSUs is at least one year. New RSUs will not be granted under the LTIP until the allocation of such awards is duly approved by the shareholders of the Company.

Phantom Units


		Weighted average
	Number of	remaining
	phantom units	contractual term
Unvested - December 31, 2017	—
Granted	265,000
Unvested - December 31, 2018	265,000	1.50

The Company granted a total of 265,000 phantom units to certain employees during the year ended December 31, 2018. The value of each unit is equal to the Company’s share price on the vesting date and is payable in cash. The phantom units vest on fixed future dates provided the recipient continues to be affiliated with Vista on those dates. Unrecognized compensation expense on these units is based on the Company’s stock price at year end. The Company accounts for these units as awards classified as liabilities with $23 included in current liabilities as of December 31, 2018. The Company recognized $23 of compensation expense for these options in the year ended December 31, 2018.

Weighted Average Common Shares


	At December 31,
	2018	2017
Basic common shares	99,738,461	98,627,255
Effect of dilutive stock-based awards	—	—
Diluted common shares	99,738,461	98,627,255

Stock options to purchase 1,319,149 common shares, unvested RSUs representing 1,002,670 common shares, and 6,514,625 warrants to purchase common shares were outstanding at December 31, 2018 but were not included in the computation of diluted weighted average common shares outstanding because their effect would have been anti-dilutive. Stock options to purchase 1,144,500 common shares, unvested RSUs representing 1,567,907 common shares, and 6,514,625 warrants to purchase common shares were outstanding at December 31, 2017 but were not included in the computation of diluted weighted average common shares outstanding because their effect would have been anti-dilutive.

During November 2017, the Company entered into an at-the-market offering agreement (the “ATM Agreement”) with H. C. Wainwright & Co., LLC (“Wainwright”), under which the Company may, but is not obligated to, issue and sell shares of the Company’s common stock through Wainwright as sales manager in an at-the-market offering under a prospectus supplement for aggregate sales proceeds of up to $10,000 (the “ATM Program”). The ATM Agreement will remain in full force and effect until the earlier of August 31, 2020, or the date that the ATM Agreement is terminated in accordance with the terms therein. Offers or sales of common shares under the ATM Program will be made only in the United States and no offers or sales of common shares under the Agreement will be made in Canada. The common stock will be distributed at the market prices prevailing at the time of sale. As a result, prices of the common stock sold under the ATM Program may vary during the period of distribution. The ATM Agreement provides that Wainwright will be entitled to compensation for its services at a commission rate of 2.0% of the gross sales price per share of common stock sold. The Company reimbursed certain legal expenses of Wainwright totaling $50 and incurred additional accounting, legal, and regulatory costs of approximately $156 in connection with establishing the ATM Program. Such costs have been expensed as incurred during 2017. At December 31, 2018 and December 31, 2017 no offers or sales had been made under the ATM Program.