Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 67,192	$ 32,424
Accounts receivable and unbilled receivables, net of allowances of $2,582 and $5,738, respectively	196,238	190,046
Inventories	100,868	96,137
Prepaid expenses	20,700	20,392
Other current assets	12,136	13,273
Total current assets	397,134	352,272
Property and equipment, net	51,500	42,595
Long-term investment in sales-type leases, net	17,082	15,435
Goodwill	335,887	337,751
Total intangible assets, net, net carrying amount	143,686	168,107
Long-term deferred tax assets	15,197	9,454
Prepaid commissions	46,143	41,432
Other long-term assets	74,613	49,316
Total assets	1,081,242	1,016,362
Current liabilities:
Accounts payable	38,038	48,290
Accrued compensation	41,660	27,241
Accrued liabilities	43,047	35,693
Long-term debt, current portion, net	0	15,208
Deferred revenues, net	81,835	78,774
Total current liabilities	204,580	205,206
Long-term deferred revenues	10,582	10,623
Long-term deferred tax liabilities	41,484	41,446
Other long-term liabilities	9,562	9,829
Long-term debt, net	135,417	194,917
Total liabilities	401,625	462,021
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000 shares authorized; no shares issued	0	0
Common stock, $0.001 par value, 100,000 shares authorized; 49,480 and 47,577 shares issued; 40,335 and 38,432 shares outstanding, respectively	50	48
Treasury stock at cost, 9,145 shares outstanding, respectively	(185,074)	(185,074)
Additional paid-in capital	678,041	585,755
Retained earnings	197,454	159,725
Accumulated other comprehensive loss	(10,854)	(6,113)
Total stockholders’ equity	679,617	554,341
Total liabilities and stockholders’ equity	$ 1,081,242	$ 1,016,362