14.	Stock-Based Compensation

The Company’s stock-based compensation plans include the TransEnterix, Inc. Amended and Restated Incentive Compensation Plan, previously named the TransEnterix, Inc. 2007 Incentive Compensation Plan (the “Plan”), as well as options outstanding under the TransEnterix, Inc. Stock Option Plan (the “2006 Plan”). As part of the Merger, options outstanding, whether vested or unvested, under the 2006 Plan were adjusted by the Exchange Ratio of 1.1533, and assumed by the Company concurrent with the closing of the Merger.

The Plan was initially approved by the majority of the stockholders on November 13, 2007. The Plan was amended on June 19, 2012 to increase the number of shares of common stock available for issuance to 1,000,000 and was amended on October 29, 2013 to (a) increase the number of shares of common stock authorized for issuance under the Plan from 1,000,000 shares of common stock to 4,940,000 shares of common stock, (b) increase the per-person award limitations for options or stock appreciation rights from 200,000 to 1,000,000 shares and for restricted stock, deferred stock, performance shares and/or other stock-based awards from 100,000 to 500,000 shares, and (c) change the name of the Plan to reflect the Merger-related change. The Plan was again amended on May 7, 2015 to (i) increase the number of shares reserved for issuance under the Plan to 11,940,000 shares; (ii) extend the term of the Plan until May 7, 2025; and (iii) make other changes and updates to the Plan and was further amended in October 2015 to add French Sub-Plan amendments applicable to awards made to France-based employees. The Plan was further amended on June 8, 2016 to (a) approve an increase in the number of shares reserved for issuance under the Plan to 18,940,000 shares and (b) establish maximum equity award limits for initial awards and annual awards to non-employee directors. The Plan was subsequently amended as of May 25, 2017, increasing the number of shares of Common Stock authorized under the Plan to 25,940,000.

The October 2013, May 2015, June 2016 and May 2017 amendments were approved by the Board of Directors and stockholders; the French Sub-Plan was approved by the Board of Directors. Under the Plan, which is administered by the Compensation Committee, the Company may grant stock options, stock appreciation rights, restricted stock and/or deferred stock to employees, officers, directors, consultants and vendors. The exercise price of stock options or stock appreciation rights may not be less than the fair market value of the Company’s shares at the date of grant. Additionally, no stock options or stock appreciation rights granted under the Plan may have a term exceeding ten years.

The 2006 Plan was adopted and approved by stockholders in September 2006 and provided for the granting of up to 80,000 stock options to employees, directors, and consultants. Under the 2006 Plan, both employees and non-employees were eligible for such stock options. In 2009, the 2006 Plan was amended to increase the total options pool to 1,110,053. In 2011, the 2006 Plan was amended to increase the total options pool to 3,378,189. The amendments were approved by the Board of Directors and stockholders. The Board of Directors had the authority to administer the plan and determine, among other things, the exercise price, term and dates of the exercise of all options at their grant date. Under the 2006 Plan, options become vested generally over four years, and expire not more than 10 years after the date of grant. As part of the Merger, options outstanding under the 2006 Plan were adjusted by the Conversion Ratio, and remain in existence as options of TransEnterix.

During the years ended December 31, 2017, 2016 and 2015, the Company recognized $7,078,000, $5,033,000 and $3,311,000, respectively, of stock-based compensation expense, including stock options and restricted stock units.

The Company recognizes as expense, the grant-date fair value of stock options and other stock based compensation issued to employees and non-employee directors over the requisite service periods, which are typically the vesting periods. The Company uses the Black-Scholes-Merton model to estimate the fair value of its stock-based payments. The volatility assumption used in the Black-Scholes-Merton model is based on the calculated historical volatility based on an analysis of reported data for a peer group of companies as well as the Company’s historical volatility. The expected term of options granted by the Company has been determined based upon the simplified method, because the Company does not have sufficient historical information regarding its options to derive the expected term. Under this approach, the expected term is the mid-point between the weighted average of vesting period and the contractual term. The risk-free interest rate is based on U.S. Treasury rates whose term is consistent with the expected life of the stock options. The Company has not paid and does not anticipate paying cash dividends on its shares of common stock; therefore, the expected dividend yield is assumed to be zero. The Company estimates forfeitures based on the historical experience of the Company and adjusts the estimated forfeiture rate based upon actual experience.

The fair value of options granted were estimated using the Black-Scholes-Merton option pricing model based on the assumptions in the table below:

	Years ended December 31,
	2017		2016		2015
Expected dividend yield		0%		0%		0%
Expected volatility	70% - 72%		47%		45% - 56%
Risk-free interest rate	1.84% - 2.29%		1.13% - 2.09%		1.44% - 1.95%
Expected life (in years)	5.5 - 6.3		5.5 - 6.3		5.5 - 6.3

The following table summarizes the Company’s stock option activity, including grants to non-employees, for the year ended December 31, 2017:

						Weighted-
						Average
				Weighted-		Remaining
	Number of			Average		Contractual
	Shares			Exercise Price		Term (Years)
Options outstanding at December 31, 2016		12,488,551		$	2.66		8.08
Granted		4,746,250			1.25
Forfeited		(574,773	)		2.35
Cancelled		(227,419	)		4.16
Exercised		(738,934	)		0.59
Options outstanding at December 31, 2017		15,693,675		$	2.32		7.78

The following table summarizes information about stock options outstanding at December 31, 2017:

					Weighted
					Average
			Weighted		Remaining
	Number of		Average		Contractual
	Shares		Exercise Price		Term (Years)
Exercisable at December 31, 2017		7,113,007	$	2.78		6.78
Vested or expected to vest at December 31, 2017		15,195,280	$	2.34		7.75

The aggregate intrinsic value of stock options outstanding, exercisable, and vested or expected to vest at December 31, 2017 was approximately $5.2 million, $1.6 million, and $4.9 million, respectively. This amount is before applicable income taxes and represents the closing market price of the Company’s common stock at December 31, 2017 less the exercise price, multiplied by the number of stock options that had an exercise price that is less than the closing market price. This amount represents the amount that would have been received by the optionees had these stock options been exercised on that date.

The total intrinsic value of options exercised during 2017, 2016 and 2015 was approximately $2,179,000, $519,000 and $1,603,000, respectively.

The Company granted 4,746,250, 5,368,755 and 4,407,758 options to employees and non-employees during the years ended December 31, 2017, 2016 and 2015, respectively, with a weighted-average grant date fair value of $0.82, $1.30 and $1.37, respectively.

As of December 31, 2017, the Company had future employee stock-based compensation expense of approximately $8,457,000 related to unvested share awards, which is expected to be recognized over an estimated weighted-average period of 2.5 years.