Years Ended December 31,

2019

2018

2017

(in thousands)

Interest expense related to debt, including commitment fees

$

—

$

(257)

$

(997)

Deferred finance cost amortization

—

(191)

(369)

Interest income

733

270

7

Other interest expense not related to debt

—

33

(55)

Interest income (expense), net

$

733

$

(145)

$

(1,414)

Average effective interest rate, excluding commitment fees

N/A

7.09%

6.72%