The Non-Qualified Stock Option Plan was a stockholder-approved plan. As of December 31, 2019, there were 280,000 options exercised during the life of the plan and 0 that remain outstanding. The Non-Qualified Stock Option Plan has been replaced by the 2012 Omnibus Equity Incentive Plan, so no further options are available for grant.

In December 2004, the Company’s stockholders approved the Omnibus Stock Option Plan. Authorized shares in this plan were 5,500,000. As of December 31, 2019, there were 813,644 options exercised during the life of the plan and 3,126,356 options remain outstanding. The 2004 Omnibus Stock Option Plan has been replaced by the 2012 Omnibus Equity Incentive Plan, so no further options are available for grant.

In December 2012, the Company’s stockholders approved the Company’s 2012 Omnibus Equity Incentive Plan to replace all prior plans (“Prior Plans”). The Prior Plans remain in effect until all awards granted under those plans have been exercised, forfeited, canceled, expired or otherwise terminated. In connection with the approval of such plan, all stock options, totaling 1,677,500 formerly available for new awards under the Prior Plans were transferred to the 2012 Omnibus Equity Incentive Plan.

During the Company's Annual Meeting of Stockholders, stockholders approved amendments to the Company's 2012 Omnibus Equity Incentive Plan increasing the number of shares of Common Stock reserved and available for grant by 4,000,000 in May 2014, 2,000,000 in May 2017 and 3,000,000 in March 2019, resulting in a total of 10,677,500 reserved shares.

Stock options granted under this plan vest either (i) upon achievement of a specified performance goal, (ii) immediately, (iii) one year after grant date, (iv) monthly over a one year period, (v) annually over a five year period, (vi) 50% two years after grant date and the remaining 50% monthly over the next two years, or (vii) 40% two years after grant date and the remaining 60% monthly over the next three years. The maximum term is ten years.

RSUs granted under this plan vest either (i) immediately, (ii) annually over a three year period, (iii) annually over a five year period, or (iv) 40% two years after grant date and the remaining 60% monthly over the next three years.

As of December 31, 2019, there were 1,207,258 options exercised and 54,329 RSUs and SGs issued, during the life of the plan. There were 7,020,538 shares remaining outstanding, leaving 2,395,375 available for grant.

The following table summarizes option activity under all plans during the years ending December 31, 2019, and 2018 and shows the exercisable shares as of December 31, 2019:



Stock Option Activity
	Number of Shares		Weighted Average Exercise Price per Share
Options Outstanding January 1, 2018	7,328,131		$	10.16
Granted	1,390,014		24.46
Forfeited	(230,779	)	21.47
Exercised	(357,373	)	10.49
Expired	(39,357	)	22.24
Options Outstanding December 31, 2018	8,090,636		12.22
Granted	3,067,888		14.52
Forfeited	(533,503	)	20.65
Exercised	(383,319	)	13.99
Expired	(109,140	)	23.86
Options Outstanding December 31, 2019	10,132,562		12.28
Exercisable December 31, 2019	6,231,099		9.17

The cash received from the exercise of options during the year ending December 31, 2019 was $5.4 million and the tax benefit realized was $0 for the same period. Upon exercise, shares are issued from shares authorized and held in reserve. The intrinsic value of options exercised was $2.3 million, $4.6 million and $12.1 million for the years ended December 31, 2019, 2018 and 2017, respectively.

The total fair value of options vesting during the period was $9.9 million, $13.4 million, and $12.0 million for the years ended December 31, 2019, 2018 and 2017, respectively.

The Company accounts for all option grants using the Black-Scholes option pricing model. The table below summarizes the inputs used to calculate the estimated fair value of options awarded for the years ended December 31:



Black-Scholes Assumptions for Options Granted
	2019			2018			2017
Expected term (in years)	6.28			6.01			6.23
Volatility	60		%	66		%	77		%
Expected dividends	—			—			—
Risk free interest rates	2.1		%	2.7		%	2.1		%
Estimated forfeitures	—		%	—		%	—		%
Weighted average fair value	$	8.33		$	14.87		$	16.24

In general, option awards have a requisite service period and unvested options are forfeited upon employee or consultant termination. In 2017, the Company implemented ASU 2016-09, Compensation-Stock Compensation (Topic 718); Improvements to Employee Share-Based Payment Accounting, and made a policy election to account for forfeitures as they occur.

The following table shows summary information for outstanding options and options that are exercisable (vested) as of December 31, 2019:



Stock Option Supplemental Information
	Options Outstanding		Options Exercisable
Number of options	10,132,562		6,231,099
Weighted average remaining contractual term (in years)	5.64		3.75
Weighted average exercise price	$	12.28	$	9.17
Weighted average fair value	$	8.10	$	6.16
Aggregate intrinsic value (in millions)	$	64.2	$	57.2

The aggregate intrinsic value in the table above represents the total pretax intrinsic value that would have been received by the option holders had all option holders exercised their options on that date. It is calculated as the difference between the Company’s closing stock price of $16.90 on the last trading day of 2019 and the exercise price multiplied by the number of shares for options where the exercise price is below the closing stock price. This amount changes based on the fair market value of the Company’s stock.



RSU and SG Activity
	Number of Shares		Weighted Average Grant Date Fair Value per Share
RSUs & SGs Outstanding January 1, 2018	24,150		$	20.91
Granted	76,000		17.33
Forfeited	—		—
Vested/released	(24,150	)	16.58
RSUs & SGs outstanding December 31, 2018	76,000		18.70
Granted	11,000		20.32
Forfeited	(60,500	)	19.74
Vested/released	(12,168	)	17.43
RSUs & SGs outstanding December 31, 2019	14,332		16.66

The total fair value of RSUs and SGs vested and released during the period was $0.2 million, $0.4 million, and $0.4 million for the years ending December 31, 2019, 2018 and 2017, respectively.

The Company records compensation cost based on the fair value of the award. The table below summarizes the weighted average fair value of RSUs and SGs awarded for the years ending December 31:

The expense and tax benefits recognized on the Company’s consolidated statements of operations and comprehensive loss related to options for the years ending December 31 (in thousands):



Equity-Based Compensation Expenses and Tax Benefit (in thousands)
	2019		2018		2017
Cost of Sales	$	277	$	189	$	99
Research and development	4,115		4,760		3,738
Sales, general and administrative	8,226		9,473		10,096
Total equity-based compensation expense	$	12,618	$	14,422	$	13,933
Recognized tax benefit	$	—	$	—	$	—

For years ended December 31, 2019, 2018 and 2017, $0.4 million,$0.5 million and $0.5 million of share-based compensation cost was capitalized to inventory or inventory transferred to property and equipment (also referred to as instruments), respectively.

As of December 31, 2019, unrecognized equity-based compensation cost related to unvested stock options, and unvested RSUs was $24.0 million and $0.1 million, respectively. This is expected to be recognized over the years 2020 through 2024.

Included in the above-noted stock option grants and stock compensation expense are performance-based stock options which vest only upon the achievement of certain targets. Performance-based options are generally granted at-the-money, contingently vest over a period of 1 to 2 years, depending on the nature of the performance goal, and have contractual lives of 10 years. These options were valued in the same manner as the time-based options, with the assumption that performance goals will be achieved. The inputs for expected volatility, expected dividends,

and risk-free rate used in estimating those options’ fair value are the same as the time-based options issued under the plan. The expected term for performance-based options granted in 2018 is 5 to 6 years. However, the Company only recognizes stock compensation expense to the extent that the targets are determined to be probable of being achieved, which triggers the vesting of the performance options.

In August 2018, the Company granted 225,000 performance based-options to certain employees. The performance obligations were met for 75,000 options and are exercisable as of as of December 31, 2019. Of the 225,000 performance based-options granted 100,000 performance based-options were forfeited for the performance targets not being achieved.

125,000 performance based-options were outstanding as of December 31, 2019, which included 50,000 performance based-options that had not achieved the performance targets or have started to be expensed. No performance based-options have been exercised as of December 31, 2019. The Company recognized $0.1 million and $0.7 million of stock compensation expense for performance-based stock options for the years ended December 31, 2019 and 2018, respectively.