Stock-Based Compensation Expense

3 Months Ended

Mar. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

11. Stock-Based Compensation Expense

Total stock-based compensation expense recognized in the accompanying condensed consolidated statements of operations for the three months ended March 31, 2018 and 2017 was as follows (in thousands):

	Three Months Ended March 31,
	2018		2017
Stock-based compensation	$	1,943	$	1,267

During the three months ended March 31, 2018, the Company issued 57,400 restricted units to certain employees which vest over a four-year period. The grant date fair value of the restricted stock units was $158,424 with a weighted average grant date fair value per share of $2.76.

During the three months ended March 31, 2018, the Company granted certain employees stock options to purchase an aggregate of 456,720 shares of common stock at a weighted average exercise price of $2.76 per share. The options vest over a four year period. The grant date fair value of these awards is $1.0 million with a weighted average grant date fair value of $2.10 per share, as determined using a Black-Scholes option pricing model.

As of March 31, 2018, there were $2.8 million and $3.4 million of unrecognized compensation expense related to restricted stock units and options, respectively, that vest over the vesting period.

During the three months ended March 31, 2018 and 2017, the Company recognized $1.0 million and $0.1 million of compensation costs related to the performance-based stock options, respectively. As of March 31, 2018, there was $2.4 million of unrecognized compensation costs related to stock options subject to performance conditions. The Company evaluates stock awards with performance conditions as the probability that the performance conditions will be met and uses that information to estimate the date at which those performance conditions will be met in order to properly recognize stock-based compensation expense over the requisite service period.