Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 339,358	$ 178,292
Restricted cash	1,043	1,043
Accounts receivable	76,955	143,653
Inventories	125,745	142,812
Income tax receivable, net	0	2,432
Prepaid expenses and other current assets	20,047	17,157
Total current assets	563,148	485,389
Property, plant and equipment, net	435,075	407,210
Intangible assets, net	107,861	119,597
Goodwill	49,130	49,130
Deferred tax assets, net	12,652	2,834
Other assets	5,757	6,046
Total assets	1,173,623	1,070,206
Current liabilities:
Accounts payable	38,874	41,751
Accrued expenses and other current liabilities	7,425	4,831
Accrued compensation	41,807	37,882
Contingent consideration, current portion	2,954	2,372
Income taxes payable, net	164	0
Deferred revenue, current portion	10,790	13,232
Total current liabilities	102,014	100,068
Contingent consideration, net of current portion	9,003	9,902
Long-term indebtedness	13,495	13,457
Income taxes payable	12,500	12,500
Deferred revenue, net of current portion	65,343	17,259
Other liabilities	4,619	4,675
Total liabilities	206,974	157,861
Stockholders' equity:
Preferred stock, $0.001 par value; 15,000,000 shares authorized, 0 shares issued and outstanding at both September 30, 2018 and December 31, 2017	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized, 51,403,585 shares issued and 50,186,299 shares outstanding at September 30, 2018; 50,619,808 shares issued and 49,405,365 shares outstanding at December 31, 2017	51	50
Treasury stock, at cost, 1,217,286 and 1,214,443 common shares at September 30, 2018 and December 31, 2017, respectively	(39,642)	(39,497)
Additional paid-in capital	640,178	618,416
Accumulated other comprehensive loss	(4,666)	(3,698)
Retained earnings	370,728	337,074
Total stockholders' equity	966,649	912,345
Total liabilities and stockholders' equity	$ 1,173,623	$ 1,070,206