Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 46,848	$ 48,367
Short-term investments	43,212	32,774
Accounts and notes receivable, net of allowance of $200 and $251 as of March 31, 2015 and December 31, 2014, respectively	21,022	30,735
Inventory, net	22,626	18,323
Prepaid expenses and other current assets	4,276	4,443
Deferred income tax assets, net	5,186	5,186
Total current assets	143,170	139,828
Property and equipment, net of accumulated depreciation of $34,338 and $33,906 as of March 31, 2015 and December 31, 2014, respectively	17,213	17,523
Deferred income tax assets, net	11,505	10,877
Intangible assets, net	2,965	3,115
Goodwill	2,206	2,206
Long-term investments	14,713	9,296
Other assets	4,039	2,523
Total assets	195,811	185,368
Current liabilities:
Accounts payable	7,808	7,682
Accrued liabilities	6,999	9,245
Current portion of deferred revenue	14,628	14,020
Customer deposits	647	988
Current portion of capital lease payable	39	38
Total current liabilities	30,121	31,973
Deferred revenue, net of current portion	22,443	21,668
Liability for unrecognized tax benefits	1,645	1,471
Long-term deferred compensation	1,549	1,121
Long-term portion of capital lease payable	19	29
Total liabilities	55,777	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 March 31, 2015 and December 31, 2014	0	0
Common stock, $0.00001 par value; 200,000,000 shares authorized; 53,359,345 and 53,000,867 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively	1	1
Additional paid-in capital	166,275	162,641
Treasury stock at cost, 18,139,958 shares as of March 31, 2015 and December 31, 2014	(114,645)	(114,645)
Retained earnings	88,250	81,045
Accumulated other comprehensive income	153	64
Total stockholders’ equity	140,034	129,106
Total liabilities and stockholders’ equity	$ 195,811	$ 185,368