Consolidated Statements of Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 365,635	$ 294,490	$ 348,201
Cost of revenue	152,814	129,345	151,698
Gross profit	212,821	165,145	196,503
Operating expenses:
Research and development	183,875	167,924	200,539
Sales and marketing	47,722	43,080	42,381
General and administrative	30,672	28,302	23,782
Total operating expenses	262,269	239,306	266,702
Loss from operations	(49,448)	(74,161)	(70,199)
Interest expense	(34,920)	(32,209)	(29,842)
Other income, net	11,853	2,408	3,961
Loss before income taxes	(72,515)	(103,962)	(96,080)
Provision (benefit) for income taxes	396	(8,211)	(21,176)
Net loss	$ (72,911)	$ (95,751)	$ (74,904)
Earnings per share:
Basic (in dollars per share)	$ (1.61)	$ (2.19)	$ (1.78)
Diluted (in dollars per share)	$ (1.61)	$ (2.19)	$ (1.78)
Weighted-average shares used in computing earnings per share:
Basic (in shares)	45,226,717	43,690,581	42,165,213
Diluted (in shares)	45,226,717	43,690,581	42,165,213