Note 14 - Share-based Payments

6 Months Ended

Jun. 30, 2016

Notes to Financial Statements

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

14. Share-based payments

(a)    Stock options

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model, consistent with the guidance on stock compensation. Because option-pricing models require the use of subjective assumptions, changes in these assumptions can materially affect the fair value of the options. The assumptions presented in the table below represent the weighted average of the applicable assumption used to value stock options at their grant date. The Company calculates expected volatility based on historical volatility of the Company's common shares. The expected term, which represents the period of time that options granted are expected to be outstanding, is estimated based on historical exercise experience. The Company evaluated historical exercise behavior when determining the expected term assumptions. The risk-free rate assumed in valuing the options is based on the U.S. Treasury yield curve in effect at the time of grant for the expected term of the option. The Company determines the expected dividend yield percentage by dividing the expected annual dividend by the market price of our common shares at the date of grant.

Details of stock option transactions for the three months ended June 30, 2016 and June 30, 2015 are as follows:

	Three months ended June 30 ,  2016					Three months ended June 30 , 2015
	Number of shares			Weighted average exercise price per share		Number of shares			Weighted average exercise price per share
Outstanding, beginning of period		550,641		$	10.48		943,323		$	6.23
Granted		8,000			23.37		-			-
Exercised		(51,963	)		3.52		(112,656	)		2.66
Forfeited		(4,088	)		23.83		(1,716	)		13.15
Expired		-			-		(1,875	)		2.40
Outstanding, end of period		502,590			11.30		827,076			6.69
Options exercisable, end of period		298,343		$	7.08		581,433		$	4.58

Details of stock option transactions for the six months ended June 30, 2016 and June 30, 2015 are as follows:

	Six months ended June 30 , 2016					Six months ended June 30 , 2015
	Number of shares			Weighted average exercise price per share		Number of shares			Weighted average exercise price per share
Outstanding, beginning of period		513,366		$	9.24		976,062		$	6.23
Granted		63,000			21.21		45,000			19.41
Exercised		(63,537	)		3.72		(187,653	)		2.92
Forfeited		(9,489	)		17.23		(4,458	)		12.46
Expired		(750	)		3.76		(1,875	)		2.40
Outstanding, end of period		502,590			11.30		827,076			6.69
Options exercisable, end of period		298,343		$	7.08		581,433		$	4.58

As of June 30, 2016, the exercise prices, weighted average remaining contractual life and intrinsic values of outstanding options were as follows:

			Options outstanding								Options exercisable
Exercise price			Number outstanding		Weighted average exercise price per share		Weighted average remaining contractual life (years)		Aggregate intrinsic value		Number exercisable		Weighted average exercise price per share		Weighted average remaining contractual life (years)		Aggregate intrinsic value
$2.80	-	4.48		90,513	$	2.97		1.3	$	1,936,426		90,513	$	2.97		1.3	$	1,936,426
$5.52	-	8.92		178,177		6.63		2.9		3,158,294		154,755		6.51		2.8		2,761,971
$10.16	-	14.67		29,375		10.83		4.2		397,394		10,625		12.02		3.9		131,144
$15.51	-	19.95		132,775		17.35		5.1		930,368		42,450		16.67		4.4		326,578
$21.10	-	24.96		71,750		22.36		5.9		154,620		-		-		-		-
				502,590	$	11.30		3.7	$	6,577,102		298,343	$	7.08		2.6	$	5,156,119

Total unrecognized compensation cost relating to unvested stock options at June 30, 2016, prior to the consideration of expected forfeitures, was approximately $1,336,707 and is expected to be recognized over a weighted average period of 2.1 years.

The Company recorded stock-based compensation of $190,187 and $390,415 for the three and six months ended June 30, 2016 and 2015 and $124,605 and $249,653 for the three and six months ended June 30, 2015, respectively.

The Company has not capitalized any stock-based compensation expense as part of the cost of an asset.