Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities
Net income	$ 24,025	$ 17,972	$ 10,951
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,080	4,264	3,483
Stock-based compensation expense	3,039	1,130	331
Deferred taxes	(583)	2,230	561
Excess tax benefit from stock-based compensation	(6,218)	(657)
Loss on impairment of foreign subsidiary assets			773
Loss (gain) on disposal of property and equipment	154	(10)	26
Changes in operating assets and liabilities:
Accounts receivable	(4,372)	(3,457)	(2,993)
Inventories	(829)	(2,195)	(537)
Prepaid expenses and other	(1,887)	(591)	(801)
Income taxes	4,314	37	(104)
Accounts payable	306	1,545	1,148
Accrued liabilities and other	1,277	3,267	1,174
Net cash provided by operating activities	25,306	23,535	14,012
Investing activities
Proceeds from sale of property and equipment			30
Purchases of property and equipment	(17,397)	(19,003)	(7,069)
Purchases of marketable securities	(84,219)		(1,504)
Proceeds from maturities of marketable securities	22,368	500	2,502
Net cash used in investing activities	(79,248)	(18,503)	(6,041)
Financing activities
Proceeds from initial public offering, net of offering costs	71,530
Proceeds from follow-on offering, net of offering costs	2,451
Proceeds from issuance of debt			417
Payments on debt	(388)	(4,049)	(4,702)
Proceeds from exercises of warrants and stock options	2,975	547	56
Excess tax benefit from stock-based compensation	6,218	657
Net cash provided by (used in) financing activities	82,786	(2,845)	(4,229)
Effect of exchange rate changes on cash and cash equivalents	(220)	(153)	(344)
Net increase in cash and cash equivalents	28,624	2,034	3,398
Cash and cash equivalents, beginning of period	8,135	6,101	2,703
Cash and cash equivalents, end of period	36,759	8,135	6,101
Supplemental cash flow disclosure
Cash paid for interest	63	140	256
Cash paid for taxes	$ 7,990	$ 5,358	$ 4,663