Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 37,306	$ 59,526
Short-term investments	49,711	50,254
Accounts and notes receivable, net of allowance of $292 and $322 as of June 30, 2016 and December 31, 2015, respectively	30,499	27,701
Inventory, net	21,936	15,763
Prepaid expenses and other current assets	14,323	8,165
Total current assets	153,775	161,409
Property and equipment, net of accumulated depreciation of $37,266 and $36,020 as of June 30, 2016 and December 31, 2015, respectively	22,249	21,848
Deferred income tax assets, net	15,577	13,719
Intangible assets, net	7,228	7,588
Goodwill	9,100	9,596
Long-term investments	4,594	8,525
Other assets	16,172	7,196
Total assets	228,695	229,881
Current liabilities:
Accounts payable	8,083	7,333
Accrued liabilities	10,382	8,643
Current portion of deferred revenue	31,668	20,851
Customer deposits	1,998	1,226
Current portion of notes payable and capital lease payable	62	87
Total current liabilities	52,193	38,140
Deferred revenue, net of current portion	35,098	30,190
Liability for unrecognized tax benefits	1,508	1,315
Long-term deferred compensation	2,759	2,199
Long-term business acquisition contingent consideration	0	952
Other long-term liabilities	2,707	81
Total liabilities	94,265	72,877
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.00001 par value; 25,000,000 shares authorized; no shares issued and outstanding as of June 30, 2016 and December 31, 2015	0	0
Common stock, $0.00001 par value; 200,000,000 shares authorized; 52,172,547 and 53,692,192 shares issued and outstanding as of June 30, 2016 and December 31, 2015, respectively	1	1
Additional paid-in capital	181,943	178,143
Treasury stock at cost, 20,220,227 and 18,432,158 shares as of June 30, 2016 and December 31, 2015, respectively	(155,947)	(122,201)
Retained earnings	108,091	100,978
Accumulated other comprehensive income	342	83
Total stockholders’ equity	134,430	157,004
Total liabilities and stockholders’ equity	$ 228,695	$ 229,881

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).