Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt

Schedule of outstanding debt obligations

	At December 31,
	2016		2015
Convertible Notes	$	172,500	$	172,500
Unaccreted discount on Convertible Notes		(17,149)		(22,367)
Unamortized issuance costs on Convertible Notes		(2,776)		(3,715)
	$	152,575	$	146,418
Term Notes	$	142,000	$	150,000
Unamortized issuance costs on Term Notes		(3,665)		(5,601)
	$	138,335	$	144,399

Schedule of interest expense

	Year Ended December 31,
	2016		2015		2014
Coupon interest	$	3,019	$	3,019	$	126
Amortization of issuance costs		2,875		1,462		79
Accretion of debt discount		5,237		4,932		242
Interest on credit agreement		5,128		606		—
Undrawn and other fees		341		252		179
	$	16,600	$	10,271	$	626