Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 179,507	$ 170,345
Short-term investments	134,006	148,697
Accounts receivable, net of allowances of $30.4 million and $32.2 million, respectively	243,400	244,416
Inventories	118,115	125,813
Income taxes receivable	8,952	4,565
Assets held for sale	4,200	4,200
Other current assets	57,814	41,799
Total current assets	745,994	739,835
Property and equipment, net	95,981	98,762
Restricted cash equivalents	39,809	32,531
Goodwill	395,421	403,278
Intangible assets, net	97,536	123,008
Deferred tax assets	44,384	45,083
Other assets	29,885	15,504
Total assets	1,449,010	1,458,001
Current liabilities:
Accounts payable	128,039	123,935
Accrued and other liabilities	91,026	98,090
Deferred revenue	66,581	55,833
Income taxes payable	6,501	5,309
Total current liabilities	292,147	283,167
Convertible senior notes, net	326,512	318,957
Imputed financing obligation related to build-to-suit lease	13,880	13,944
Noncurrent contingent and other liabilities	20,185	28,801
Deferred tax liabilities	8,220	11,652
Noncurrent income taxes payable	20,710	20,169
Total liabilities	681,654	676,690
Commitments and contingencies (Note 10)
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; 54,577 and 54,249 shares issued, respectively	546	542
Additional paid-in capital	769,223	745,661
Treasury stock, at cost; 10,056 and 9,070 shares, respectively	(404,603)	(375,574)
Accumulated other comprehensive income (loss)	(5,202)	8,138
Retained earnings	407,392	402,544
Total stockholders’ equity	767,356	781,311
Total liabilities and stockholders’ equity	$ 1,449,010	$ 1,458,001