Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Preferred Stock, Series A	Preferred Stock, Series B	Preferred Stock, Series C	Common Stock	Additional Paid-in Capital [Member]
Preferred Stock, Shares Outstanding		1,843,965	5,696,834	12,834,912
Preferred Stock, Value, Outstanding		$ 1,945	$ 18,536	$ 77,397
Common Stock, Shares, Outstanding					2,159,068
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, par value $0.0001					$ 1
Additional paid in capital						$ 2,754
Accumulated other comprehensive gain (loss)	$ 0
Accumulated deficit	(60,585)
Stockholders' Equity Attributable to Parent	(57,830)
Net loss	(60,080)
Stock Issued During Period, Shares, New Issues				707,680	6,555,000
Stock Issued During Period, Value, New Issues				$ 4,414	$ 0	88,903
Conversion of convertible preferred stock into common stock, shares		(1,843,965)	(5,696,834)	(13,542,592)	11,837,073
Conversion of convertible preferred stock into common stock, value	102,293	$ (1,945)	$ (18,536)	$ (81,811)	$ 1	102,292
Exercise and vesting of stock-based awards					248,978
Adjustments to Additional Paid in Capital, Exercise and Vesting of Stock-Based Awards	$ 395					395
Warrants, exercises in period	8,247
Warrants, exercises in period, value	$ 49					49
Stock-based compensation	1,728					1,728
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ (52)
Preferred Stock, Shares Outstanding		0	0	0
Preferred Stock, Value, Outstanding		$ 0	$ 0	$ 0
Common Stock, Shares, Outstanding					20,808,366
Preferred Stock, Shares Issued	0
Common stock, par value $0.0001	$ 2				$ 2
Additional paid in capital	196,121					196,121
Accumulated other comprehensive gain (loss)	(52)
Accumulated deficit	(120,665)
Stockholders' Equity Attributable to Parent	75,406
Net loss	(125,580)
Stock Issued During Period, Shares, New Issues					6,201,202
Stock Issued During Period, Value, New Issues	$ 57,227				$ 1	57,226
Exercise and vesting of stock-based awards	(128,307)				128,307
Adjustments to Additional Paid in Capital, Exercise and Vesting of Stock-Based Awards	$ 254					254
Stock Issued During Period, Shares, Employee Stock Purchase Plans	73,607
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 532					532
Warrants, exercises in period					3,041
Warrants, exercises in period, value	18					18
Stock-based compensation	6,484					6,484
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 95
Preferred Stock, Shares Outstanding		0	0	0
Preferred Stock, Value, Outstanding		$ 0	$ 0	$ 0
Common Stock, Shares, Outstanding					27,214,523
Preferred Stock, Shares Issued	0
Common stock, par value $0.0001	$ 3				$ 3
Additional paid in capital	260,635					$ 260,635
Accumulated other comprehensive gain (loss)	43
Accumulated deficit	(246,245)
Stockholders' Equity Attributable to Parent	$ 14,436