Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of Loss before Provision for Income Taxes
United States									$ (36,821,000)	$ (20,173,000)	$ (60,300,000)
Foreign									(3,733,000)	(12,006,000)	(3,419,000)
Loss before income tax benefit (provision)	(10,852,000)	(10,950,000)	(8,819,000)	(9,933,000)	(7,656,000)	(7,925,000)	(8,568,000)	(8,030,000)	(40,554,000)	(32,179,000)	(63,719,000)
Current income tax provision:
Federal									0	0	0
State									117,000	0	0
Foreign									620,000	176,000	181,000
Total current income tax provision									737,000	176,000	181,000
Deferred income tax benefit:
Federal									0	0	0
State									0	0	0
Foreign									(865,000)	(965,000)	0
Total deferred income tax benefit									(865,000)	(965,000)	0
Total income tax (benefit) provision	(97,000)	104,000	(136,000)	1,000	(239,000)	(298,000)	(334,000)	82,000	(128,000)	(789,000)	181,000
Federal statutory tax rate									34.00%	34.00%	34.00%
Effective Income Tax Rate Reconciliation
U.S. Federal tax benefit at statutory rates									(13,784,000)	(10,941,000)	(21,688,000)
State income taxes, net of federal tax benefit									(415,000)	(60,000)	(916,000)
Foreign rate differential									1,354,000	1,008,000	219,000
Preferred stock warrant charges									0	0	14,470,000
Stock based compensation									2,039,000	1,360,000	474,000
Other permanent differences									410,000	654,000	188,000
Other									76,000	(194,000)	206,000
Valuation allowance									10,192,000	7,384,000	7,228,000
Total income tax (benefit) provision	(97,000)	104,000	(136,000)	1,000	(239,000)	(298,000)	(334,000)	82,000	(128,000)	(789,000)	181,000
Deferred Tax Assets
Accrued expenses	2,029,000				1,306,000				2,029,000	1,306,000
Long-lived intangible assets — basis difference	7,846,000				5,155,000				7,846,000	5,155,000
Net operating loss carryforwards	33,823,000				24,392,000				33,823,000	24,392,000
Stock-based compensation	4,818,000				2,671,000				4,818,000	2,671,000
Deferred revenue	1,905,000				2,375,000				1,905,000	2,375,000
Deferred Tax Assets Financing Arrangements	16,705,000				0				16,705,000	0
Other	452,000				274,000				452,000	274,000
Total deferred tax assets	67,578,000				36,173,000				67,578,000	36,173,000
Valuation allowance	(48,558,000)				(34,081,000)				(48,558,000)	(34,081,000)
Deferred tax assets, net of valuation allowance	19,020,000				2,092,000				19,020,000	2,092,000
Deferred Tax Liabilities
Prepaid expenses and deferred commissions	(3,613,000)				(2,029,000)				(3,613,000)	(2,029,000)
Long-lived fixed assets — basis difference	(2,136,000)				(805,000)				(2,136,000)	(805,000)
Deferred Tax Liabilities, Financing Arrangements	(13,028,000)				0				(13,028,000)	0
Other	(120,000)				0				(120,000)	0
Total deferred tax liabilities	(18,897,000)				(2,834,000)				(18,897,000)	(2,834,000)
Net deferred tax assets (liabilities)	123,000				(742,000)				123,000	(742,000)
Federal, state and foreign net operating losses	145,800,000				152,800,000				145,800,000	152,800,000	18,000,000
Net increase to valuation allowance primarily due to additional net operating losses									14,500,000	7,400,000	7,200,000
Share-based compensation tax benefit not recognized in deferred tax assets	25,800,000								25,800,000
Undistributed foreign earnings	900,000				500,000				900,000	500,000
Potential tax impact if undistributed foreign earnings were distributed	125,000				76,000				125,000	76,000
Reconciliation of Unrecognized Tax Benefits
Balance at January 1				276,000				276,000	276,000	276,000	276,000
Additions for tax positions related to the current year									0	0	0
Balance at December 31	276,000				276,000				276,000	276,000	276,000
Reduction in tax expense if unrecognized tax benefits are recognized	$ 300,000								$ 300,000