Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 45,887	$ 48,367
Short-term investments	49,526	32,774
Accounts and notes receivable, net of allowance of $225 and $251 as of September 30, 2015 and December 31, 2014, respectively	24,328	30,735
Inventory, net	18,892	18,323
Prepaid expenses and other current assets	6,336	4,443
Deferred income tax assets, net	5,186	5,186
Total current assets	150,155	139,828
Property and equipment, net of accumulated depreciation of $35,431 and $33,906 as of September 30, 2015 and December 31, 2014, respectively	19,855	17,523
Deferred income tax assets, net	11,147	10,877
Intangible assets, net	7,812	3,115
Goodwill	9,313	2,206
Long-term investments	9,171	9,296
Other assets	6,024	2,523
Total assets	213,477	185,368
Current liabilities:
Accounts payable	6,040	7,682
Accrued liabilities	6,668	9,245
Current portion of deferred revenue	19,628	14,020
Customer deposits	572	988
Current portion of notes payable and capital lease payable	98	38
Total current liabilities	33,006	31,973
Deferred revenue, net of current portion	26,880	21,668
Liability for unrecognized tax benefits	1,198	1,471
Long-term deferred compensation	1,857	1,121
Long-term business acquisition contingent consideration	952	0
Long-term portion of notes payable and capital lease payable	98	29
Total liabilities	$ 63,991	$ 56,262
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 25,000,000 shares authorized; no shares issued and outstanding as of September 30, 2015 and December 31, 2014	$ 0	$ 0
Common stock, $0.00001 par value; 200,000,000 shares authorized; 53,604,818 and 53,000,867 shares issued and outstanding as of September 30, 2015 and December 31, 2014, respectively	1	1
Additional paid-in capital	175,766	162,641
Treasury stock at cost, 18,432,158 and 18,139,958 shares as of September 30, 2015 and December 31, 2014, respectively	(122,201)	(114,645)
Retained earnings	95,874	81,045
Accumulated other comprehensive income	46	64
Total stockholders’ equity	149,486	129,106
Total liabilities and stockholders’ equity	$ 213,477	$ 185,368

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).