Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 99,196	$ 68,795
Short-term marketable securities	48,272	39,477
Accounts receivable, net of allowance for doubtful accounts of $522 and $442 as of June 30, 2017 and December 31, 2016, respectively	42,211	34,060
Inventory	9,327	9,310
Prepaid expenses and other current assets	5,915	5,697
Income taxes receivable		445
Total current assets	204,921	157,784
Property and equipment, net	146,364	139,474
Goodwill	28,916	28,916
Other intangible assets, net	2,367	2,655
Long-term marketable securities	69,435	84,479
Other long-term assets	2,650	933
Total assets	454,653	414,241
Liabilities and shareholders' equity
Accounts payable	14,147	11,322
Accrued compensation	10,990	7,670
Accrued liabilities and other	4,530	4,435
Income taxes payable	1,383
Total current liabilities	31,050	23,427
Long-term deferred tax liabilities	8,613	7,003
Other long-term liabilities	4,186	3,978
Total liabilities	43,849	34,408
Shareholders' equity
Preferred stock, $0.001 par value, authorized 10,000,000 shares; issued and outstanding 0 shares as of each of June 30, 2017 and December 31, 2016
Common stock, $0.001 par value, authorized 150,000,000 shares; issued and outstanding 26,586,152 and 26,504,868 shares as of June 30, 2017 and December 31, 2016, respectively	27	26
Additional paid-in capital	220,975	213,857
Retained earnings	197,206	176,703
Accumulated other comprehensive loss	(7,404)	(10,753)
Total shareholders' equity	410,804	379,833
Total liabilities and shareholders' equity	$ 454,653	$ 414,241

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.