Convertible Senior Notes (Tables)

3 Months Ended

Mar. 31, 2018

Convertible Senior Notes

Convertible senior notes consist of the following (in thousands):

	March 31, 2018						December 31, 2017
	Principal/		Debt				Principal/		Debt
	Fair Value		Issuance		Net		Fair Value		Issuance		Net
	Amount		Costs		Amount		Amount		Costs		Amount
3.25% convertible senior notes (due 2020) *	$	23,490	$	―	$	23,490	$	22,469	$	―	$	22,469
4.25% convertible senior notes (due 2018)		21,178		59		21,119		21,178		103		21,075
4.875% convertible senior notes (due 2020)		113,000		1,774		111,226		113,000		1,972		111,028
Total convertible senior notes, net of debt issuance costs	$	157,668	$	1,833	$	155,835	$	156,647	$	2,075	$	154,572

* The amount presented for the 3.25% 2020 convertible senior notes within the table represents the fair value as of March 31, 2018. The principal amount of these notes is $21.5 million.