Liabilities (Tables)

3 Months Ended

Mar. 31, 2020

Liabilities

Schedule of accrued expenses and other current liabilities

	March 31,		December 31,
	2020		2019
	(in thousands)
Payroll and related benefits	$	18,909	$	15,174
Warranty		5,968		7,067
Operating lease liabilities		4,286		4,196
Interest		1,992		4,321
Professional fees		1,936		2,443
Sales, use, and other taxes		2,644		811
Restructuring liability		2,074		2,841
Other		3,759		4,390
Total	$	41,568	$	41,243

Schedule of changes in product warranty reserves

		(in thousands)
Balance - December 31, 2019	$	7,067
Warranties issued		645
Consumption of reserves		(1,708)
Changes in estimate		(36)
Balance - March 31, 2020	$	5,968

Schedule of restructuring accrual activities

	(in thousands)
Balance - December 31, 2019	$	2,841
Provision		625
Payments		(1,392)
Balance - March 31, 2020	$	2,074

Schedule of changes in deferred revenue

	(in thousands)
Balance - December 31, 2019	$	28,249
Deferral of revenue		5,089
Recognition of previously deferred revenue		(8,607)
Balance - March 31, 2020	$	24,731

Schedule of carrying value of Convertible Senior Notes

	March 31,		December 31,
	2020		2019
	(in thousands)
Principal amount	$	345,000	$	345,000
Unamortized debt discount		(37,804)		(40,820)
Unamortized transaction costs		(3,808)		(4,112)
Net carrying value	$	303,388	$	300,068

Schedule of interest expense related to Convertible Senior Notes

	Three months ended March 31,
	2020		2019
	(in thousands)
Cash Interest Expense
Coupon interest expense	$	2,329	$	2,329
Non-Cash Interest Expense
Amortization of debt discount		3,016		2,799
Amortization of transaction costs		304		282
Total Interest Expense	$	5,649	$	5,410