Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 91,905	$ 125,225
Short-term marketable securities	38,194	35,437
Accounts receivable, net of allowance for doubtful accounts of $1,821 and $952 as of March 31, 2020 and December 31, 2019, respectively	62,091	57,450
Inventory	10,507	10,075
Prepaid expenses and other current assets	9,777	8,232
Total current assets	212,474	236,419
Property and equipment, net	268,001	263,712
Goodwill	128,752	128,752
Other intangible assets, net	16,615	17,369
Long-term marketable securities	37,077	12,960
Operating lease assets	10,548	11,425
Other long-term assets	4,623	3,030
Total assets	678,090	673,667
Current liabilities
Accounts payable	18,219	16,804
Accrued compensation	12,460	15,058
Accrued liabilities and other	12,950	11,057
Current operating lease liabilities	3,254	3,340
Income taxes payable	414	1,322
Total current liabilities	47,297	47,581
Long-term operating lease liabilities	7,871	8,565
Long-term deferred tax liabilities	29,652	26,283
Other long-term liabilities	5,530	5,448
Total liabilities	90,350	87,877
Shareholders' equity
Preferred stock, $0.001 par value, authorized 10,000,000 shares; issued and outstanding 0 shares as of each of March 31, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value, authorized 150,000,000 shares; issued and outstanding 26,648,524 and 26,786,459 shares as of March 31, 2020 and December 31, 2019, respectively	27	27
Additional paid-in capital	268,574	268,059
Retained earnings	329,137	324,722
Accumulated other comprehensive loss	(9,998)	(7,018)
Total shareholders' equity	587,740	585,790
Total liabilities and shareholders' equity	$ 678,090	$ 673,667