Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Option Activity

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

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at January 1, 2020		1,168,222		$	16.77
Granted		415,502		$	5.81
Exercised		—		$	—
Forfeited		(27,518	)	$	29.73
Outstanding at March 31, 2020		1,556,206		$	13.62		7.79	$	—
Exercisable at March 31, 2020		734,889		$	19.02		6.18	$	—

Assumptions used in Black-Scholes Pricing Model for New Grants

The fair value of stock options subject only to service or performance conditions that are granted to employees is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in the table below.

	Three Months Ended March 31,
	2020		2019
Volatility factor	94.37% - 94.51%		88.27% - 90.49%
Expected term (in years)	6.25		5.50 - 6.25
Risk-free interest rates	1.52% - 1.67%		2.24% - 2.55%
Dividend yield		—		—