6. Stock-based Compensation

On June 13, 2017, the Company granted options (the “Options”) to acquire shares of the Company’s common stock (the “Shares”) to Dr. Marnix Bosch, the Chief Technical Officer of the Company, and Dr. Alton Boynton, the Chief Scientific Officer of the Company. The Options were granted pursuant to the Second Amended and Restated Northwest Biotherapeutics, Inc. 2007 Stock Plan (the “Equity Plan”). The Equity Plan provides for awards of various types of equity securities (including common stock, restricted stock units, options and/or other derivative securities) to employees and directors of the Company.

Dr. Bosch received Options exercisable for 7,940,182 Shares and Dr. Boynton received Options exercisable for 3,402,935 Shares. The Options are exercisable at a price of $0.25 per share, and have a 5-year exercise period. The Options granted to Dr. Bosch and Dr. Boynton are subject to vesting requirements. 50% of the Options vested on the grant date, and 50% will vest over a 24-month period in equal monthly installments, provided that the recipient continues to be employed by the Company. The unvested portions of the Options are subject to accelerated vesting upon (i) a change of effective control of the Company, (ii) the filing of the first Biologics License Application or other application for product approval in any jurisdiction, (iii) completion of any randomized clinical trial that meets its endpoint(s) (Phase II or Phase III), (iv) decision by the Board, in its discretion or (v) the death of the recipient.

The following table summarizes stock option activities for the Company’s option plans for the six months ended June 30, 2017 (amount in thousands, except per share number):

	Number of Options		Weighted Average Exercise Price		Total Intrinsic Value		Weighted Average Remaining Contractual Life (in years)
Outstanding as of December 31, 2016		1,551	$	10.56	$	-		1.9
Granted		11,343		0.25		-		5.0
Forfeited/expired		(238)		9.90		-		-
Outstanding as of June 30, 2017		12,656	$	1.32		-		4.6
Options vested and exercisable		6,546	$	1.63	$	-		4.5

The following assumptions were used to compute the fair value of stock options granted during the six months ended June 30, 2017:

	For the Six Months
	Ended
	June 30, 2017
Exercise price	$	0.25
Expected term (years)		2.8
Expected stock price volatility		96	%
Risk-free rate of interest		2	%

The Company recorded stock based compensation expense of $373,000, which was included as part of research and development expenses for the six months ended June 30, 2017. The weighted average grant date fair value was approximately $0.7 million and the unrecognized compensation cost was approximately $0.3 million as of June 30, 2017, and will be recognized over the next 2.2 years. The Company records the forfeitures, if any, when such forfeitures occur.

The risk-free rate is based on the rate of U.S Treasury zero-coupon issues with a remaining term equal to the expected term of the option grants. Expected volatility is based on the historical volatility of the Company’s common stock using the daily closing price of the Company’s common stock. The expected term represents the period that the Company’s stock-based awards are expected to be outstanding.