Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 92,330	$ 75,105
Short-term investments	4,475	6,862
Accounts and notes receivable, net of allowance of $880 and $754 as of March 31, 2018 and December 31, 2017, respectively	87,849	56,064
Contract assets, net	9,278	0
Inventory	43,104	45,465
Prepaid expenses and other current assets	21,934	21,696
Total current assets	258,970	205,192
Property and equipment, net of accumulated depreciation of $37,518 and $36,477 as of March 31, 2018 and December 31, 2017, respectively	31,175	31,172
Deferred income tax assets, net	14,200	15,755
Intangible assets, net	17,496	18,823
Goodwill	14,947	14,927
Long-term notes receivable, net of current portion	34,624	36,877
Other assets	21,573	15,366
Total assets	392,985	338,112
Current liabilities:
Accounts payable	11,692	8,592
Accrued liabilities	34,869	23,502
Current portion of deferred revenue	76,141	70,401
Customer deposits	3,155	3,673
Current portion of business acquisition contingent consideration	2,505	1,693
Other current liabilities	348	89
Total current liabilities	128,710	107,950
Deferred revenue, net of current portion	58,003	54,881
Liability for unrecognized tax benefits	1,810	1,706
Long-term deferred compensation	3,998	3,859
Business acquisition contingent consideration, net of current portion	201	1,048
Other long-term liabilities	934	1,224
Total liabilities	193,656	170,668
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 25,000,000 shares authorized; no shares issued and outstanding as of March 31, 2018 and December 31, 2017	0	0
Common stock, $0.00001 par value; 200,000,000 shares authorized; 53,307,083 and 52,969,869 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	1	1
Additional paid-in capital	202,344	201,672
Treasury stock at cost, 20,220,227 shares as of March 31, 2018 and December 31, 2017	(155,947)	(155,947)
Retained earnings	155,105	123,185
Accumulated other comprehensive loss	(2,174)	(1,467)
Total stockholders’ equity	199,329	167,444
Total liabilities and stockholders’ equity	$ 392,985	$ 338,112

The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively.

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- Definition

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).