Consolidated balance sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 27,681	$ 21,071
Restricted cash	161	165
Short-term investments	35,481	13,567
Accounts receivable, net	8,168	3,571
Inventories	28,570	34,312
Other inventory supplies	12,693	12,533
Prepaid expenses and other current assets	1,087	1,186
Total current assets	113,841	86,405
Property and equipment, net	113,637	115,220
Other assets	1,346	1,070
Total assets	228,824	202,695
Liabilities and stockholders' equity
Accounts payable	5,676	4,465
Accrued payroll	313	369
Accrued and other current liabilities	1,212	867
Corporate income and franchise taxes	97	192
Accrued real estate taxes	382	336
Advance payments	755	408
Total current liabilities	8,435	6,637
Deferred tax liability	162	267
Total liabilities	8,597	6,904
Commitments and contingencies
Stockholders' equity
Preferred stock, $0.001 par value, 5,000,000 undesignated shares authorized, no shares issued or outstanding
Common stock, $0.001 par value, 40,000,000 shares authorized and 27,931,601 and 24,433,523 shares issued; 26,156,757 and 22,658,679 shares outstanding	28	25
Additional paid-in capital	371,417	335,935
Treasury stock, at cost, 1,774,844 shares	(12,148)	(12,148)
Accumulated other comprehensive loss	(573)	(418)
Accumulated deficit	(138,497)	(127,603)
Total stockholders' equity	220,227	195,791
Total liabilities and stockholders' equity	$ 228,824	$ 202,695