Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 163,077	$ 170,345
Short-term investments, available for sale	140,659	148,697
Accounts receivable, net of allowances of $29.6 million and $32.2 million, respectively	251,227	244,416
Inventories	123,824	125,813
Income taxes receivable	10,241	4,565
Assets held for sale	4,200	4,200
Other current assets	49,731	41,799
Total current assets	742,959	739,835
Property and equipment, net	99,333	98,762
Restricted cash equivalents and investments	35,733	32,531
Goodwill	406,876	403,278
Intangible assets, net	111,812	123,008
Deferred tax assets	40,931	45,083
Other assets	27,246	15,504
Total assets	1,464,890	1,458,001
Current liabilities:
Accounts payable	119,842	123,935
Accrued and other liabilities	97,657	98,090
Deferred revenue	68,912	55,833
Income taxes payable	5,427	5,309
Total current liabilities	291,838	283,167
Convertible senior notes, net	322,709	318,957
Imputed financing obligation related to build-to-suit lease	13,912	13,944
Noncurrent contingent and other liabilities	24,748	28,801
Deferred tax liabilities	10,375	11,652
Noncurrent income taxes payable	19,666	20,169
Total liabilities	683,248	676,690
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock, $0.01 par value; 5,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.01 par value; 150,000 shares authorized; 54,490 and 54,249 shares issued, respectively	545	542
Additional paid-in capital	757,438	745,661
Treasury stock, at cost; 9,685 and 9,070 shares, respectively	(393,175)	(375,574)
Accumulated other comprehensive income	13,211	8,138
Retained earnings	403,623	402,544
Total stockholders' equity	781,642	781,311
Total liabilities and stockholders' equity	$ 1,464,890	$ 1,458,001