8. Stock-Based Compensation

The following table summarizes the stock option and award activity for the three months ended March 31, 2020:


		Options Outstanding
			Weighted-		Weighted-
	Options and		Average		Average
	Awards		Exercise		Remaining	Aggregate
	Available for	Number of	Price Per		Contractual	Intrinsic
	Grant	Options	Share		Life (years)	Value
						(In thousands)
Balance—December 31, 2019	638,227	1,931,903	$	7.17	6.5	$	188
Authorized	542,452
RSUs granted	(228,013)
RSUs cancelled/forfeited	24,697
Options granted	(631,055)	631,055	$	2.30
Options cancelled/forfeited	120,313	(125,834)	$	8.08
Balance—March 31, 2020	466,621	2,437,124	$	5.86	7.5	$	225
Options exercisable—March 31, 2020		1,133,244	$	7.08	5.6	$	—

The total grant date fair value of options vested was $799,000 and $710,000 during the three months ended March 31, 2020 and 2019, respectively.

The weighted-average grant date fair value of employee options granted was $1.52 and $4.00 per share during the three months ended March 31, 2020 and 2019, respectively.

2016 Employee Stock Purchase Plan

In January 2020, there was an increase of 180,817 shares reserved for issuance under the Company’s Employee Stock Purchase Plan (ESPP). The Company had 576,817 shares available for future issuance under the Company’s ESPP as of March 31, 2020. Employees did not purchase any shares during the three months ended March 31, 2020 and 2019.

Restricted Stock Units

The following table summarizes Restricted Stock Units (RSUs) activity for the three months ended March 31, 2020:


	RSUs Outstanding
		Weighted-
		Average
	Number of	Grant Date
	Restricted Stock	Fair Value Per
	Units	Share
Balance—December 31, 2019	211,962	$	6.97
Granted	228,013		3.08
Vested	(88,375)		5.90
Cancelled/forfeited	(24,697)		7.59
Balance—March 31, 2020	326,903	$	4.50

The fair value of RSUs is determined on the date of grant based on the market price of the Company’s common stock on that date. As of March 31, 2020, there was $1.1 million of unrecognized stock-based compensation expense related to RSUs to be recognized over a weighted-average period of 2.9 years.

Stock-based Compensation Expense

As of March 31, 2020, there was $4.2 million of total unrecognized compensation expense related to unvested options which is expected to be recognized over a weighted-average period of 3.1 years. Compensation cost capitalized within inventory at March 31, 2020 and at December 31, 2019 was not material.