UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 121,626	$ 70,594
Marketable securities	58,414	63,167
Total cash, cash equivalents, and marketable securities	180,040	133,761
Trade accounts receivable, net of allowance of $5,590 and $4,126	217,020	265,028
Income taxes receivable	22,081	14,155
Other current assets	18,505	12,188
Total current assets	437,646	425,132
Property and equipment, net	38,881	38,281
Deferred income taxes	71,096	69,898
Long-term other assets	4,615	3,990
Intangible assets, net	37,844	44,191
Goodwill	72,890	73,164
Total assets	662,972	654,656
Current liabilities:
Accounts payable	13,500	14,414
Accrued expenses	38,237	36,751
Accrued compensation and related expenses	44,287	60,660
Deferred revenue	169,926	175,647
Total current liabilities	265,950	287,472
Income taxes payable	4,438	4,263
Long-term deferred revenue	8,431	10,989
Other long-term liabilities	15,518	16,043
Total liabilities	294,337	318,767
Stockholders' equity:
Preferred stock, 1,000 shares authorized; no shares issued and outstanding
Common stock, 200,000 shares authorized; 77,604 shares and 76,591 shares issued and outstanding	776	766
Additional paid-in capital	140,088	143,903
Retained earnings	232,100	198,315
Accumulated other comprehensive loss	(4,329)	(7,095)
Total stockholders' equity	368,635	335,889
Total liabilities and stockholders' equity	$ 662,972	$ 654,656

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.