CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net loss	$ (14,984,321)	$ (23,368,283)	$ (35,375,621)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization	3,314,360	4,107,761	5,644,682
Share-based payment compensation	4,587,282	5,493,689	7,866,384
Non-cash professional services expenses	27,487	24,369	819,185
Realized (gain) loss on marketable securities	(905)	0	90,761
Impairment of cost method investments	10,725	41,780	0
Provision for returns and doubtful accounts	357,301	120,992	1,211,838
Deferred income tax provision	(83,350)	(160,434)	16,075,130
Changes in operating assets and liabilities:
Accounts receivable	4,849,209	3,830,769	438,529
Prepaid expenses and other current assets	(889,278)	(333,732)	826,643
Inventory	1,126,188	(359,348)	(1,080,002)
Other assets	31,837	48,135	204,657
Accounts payable	(101,784)	1,446,111	(96,236)
Accrued expenses and other liabilities	(660,428)	8,670,790	324,726
Deferred revenue	(2,852,793)	3,576,167	1,320,820
Net cash (used in) provided by operating activities	(5,268,470)	3,138,766	(1,728,504)
Cash flows from investing activities:
Sales of marketable securities	32,332,954	22,098,206	34,148,774
Purchases of marketable securities	(21,267,582)	(24,101,138)	(27,586,592)
Transfer to restricted cash	(750,000)	0	0
Purchases of property and equipment	(2,487,128)	(2,220,380)	(2,700,378)
Capitalized software development costs	(461,555)	(1,001,025)	(107,206)
Security deposits	(29,746)	(48,238)	9,081
Purchase of intangible assets	(101,642)	(127,890)	(129,306)
Net cash provided by (used in) investing activities	7,235,301	(5,400,465)	3,634,373
Cash flows from financing activities:
Proceeds from exercise of stock options	738,184	920,106	409,889
Net cash provided by financing activities	738,184	920,106	409,889
Effect of exchange rate changes on cash and cash equivalents	(311,241)	(243,268)	(225,731)
Net increase (decrease) in cash and cash equivalents	2,393,774	(1,584,861)	2,090,027
Cash and cash equivalents, beginning of period	16,257,694	17,842,555	15,752,528
Cash and cash equivalents, end of period	18,651,468	16,257,694	17,842,555
Cash paid for income taxes	$ 688,164	$ 1,221,294	$ 721,159