Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 163,606	$ 178,292
Restricted cash	1,043	1,043
Accounts receivable	122,090	143,653
Inventories	155,196	142,812
Income tax receivable, net	7,044	2,432
Prepaid expenses and other current assets	27,670	17,157
Total current assets	476,649	485,389
Property, plant and equipment, net	411,269	407,210
Intangible assets, net	115,685	119,597
Goodwill	49,130	49,130
Deferred tax assets, net	12,656	2,834
Other assets	3,078	6,046
Total assets	1,068,467	1,070,206
Current liabilities:
Accounts payable	46,216	41,751
Accrued expenses and other current liabilities	6,840	4,831
Accrued compensation	24,513	37,882
Contingent consideration, current portion	2,337	2,372
Deferred revenue, current portion	6,964	13,232
Total current liabilities	86,870	100,068
Contingent consideration, net of current portion	10,133	9,902
Long-term indebtedness	13,469	13,457
Income taxes payable	12,500	12,500
Deferred revenue, net of current portion	59,365	17,259
Other liabilities	4,850	4,675
Total liabilities	187,187	157,861
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 15,000,000 shares authorized, 0 shares issued and outstanding at both March 31, 2018 and December 31, 2017	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized, 51,025,978 shares issued and 49,808,692 shares outstanding at March 31, 2018; 50,619,808 shares issued and 49,405,365 shares outstanding at December 31, 2017	50	50
Treasury stock, at cost, 1,217,286 and 1,214,443 common shares at March 31, 2018 and December 31, 2017, respectively	(39,642)	(39,497)
Additional paid-in capital	624,484	618,416
Accumulated other comprehensive loss	(3,251)	(3,698)
Retained earnings	299,639	337,074
Total stockholders' equity	881,280	912,345
Total liabilities and stockholders' equity	$ 1,068,467	$ 1,070,206